ifeu Institut für Energieund Umweltforschung
Heidelberg GmbH
Aluminium and
Renewable Energy Systems –
Prospects for the Sustainable
Generation of Electricity and Heat
Final version
commissioned by the International Aluminium Institute
Jan Maurice Bödeker (project management)
Marc Bauer
Dr. Martin Pehnt
Heidelberg, September 2010
Aluminium and Renewable Energy Systems
IFEU
Aluminium and Renewable Energy Systems –
Prospects for the Sustainable Generation of Electricity and Heat
Executive summary
Renewable energy technologies offer a large market opportunity for aluminium. In the best
case scenarios, renewable energy technologies would introduce a market increase of up to
10 % additional aluminium use. This is due to:

the large area of energy collection (e. g. module or collector surface) of renewable
energy systems;

the requirement of solar-directed installation (e. g. mounting and frames of solar
power plants)

the expected dynamic market development (high expansion targets in many countries).
In other technology areas aluminium has to compete with other materials (e. g. steel and
glass for solar thermal power plants). Increasingly, within renewable energy technologies,
aluminium is already used to a large extent (e. g. PV and solar collectors).
There has been rapid development in commercially viable renewable energy systems in recent years to meet the growing demand for the sustainable generation of electricity and heat
in both developed and developing countries. Aluminium plays an important role as one of the
key materials in a wide range of renewable energy systems, namely solar thermal collectors,
wind turbines, photovoltaic systems, solar cookers and concentrating solar thermal power
plants.
This study “Aluminium and Renewable Energy Systems – Prospects for the Sustainable
Generation of Electricity and Heat”, commissioned by the International Aluminium Institute
(IAI), assesses the present and future use of aluminium in selected renewable energy
systems for the years 2020, 2030, and 2050 under different technology development
pathways and market conditions. The use of aluminium depends heavily on both the market growth of the given renewable energy systems as well as the specific use of aluminium in
the respective technology. To address this bandwidth three scenarios with two variations
(sub-scenarios) were defined in this study. An optimistic SCENARIO HIGH assumes maximum specific aluminium use and optimistic rates of expansion of installed capacities,
whereas SCENARIO LOW assumes pessimistic estimates regarding the specific aluminium
use and the expansion of renewable energy systems. However, those two scenarios are to
be interpreted as the upper and the lower end of the scenario funnel. A more likely outcome
is SCENARIO BEST ESTIMATE based on moderate assumptions regarding the growth rate
of the renewable energy systems. It is differentiated into three sub-scenarios, which assume
a minimum, moderate and maximum specific aluminium use (BEST ESTIMATE Minus, BEST
ESTIMATE and BEST ESTIMATE Plus, respectively).
In addition, the energetic and environmental benefits namely generated electricity and heat
as well as the CO2 abatement potential of renewable energy systems that use aluminium are
projected for the three reference scenarios.
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Specific aluminium use (kg/kW)
The specific aluminium (kg per kilowatt) used in the technologies differs significantly (see
Figure 1). Particularly PV and CSP use high amounts of aluminium in the Al moderate, and
even more in the Al maximum scenario. This is due to rather high shares of aluminium in the
components as well as rather low conversion efficiencies (e. g. compared to solar thermal
collectors). It has to be noted that in Figure 1 the aluminium use is normalized to one kW
heat for solar thermal collectors and one kW electricity for the other technologies.
140
120
100
80
Al maximum
60
Al moderate
40
Al minimum
20
0
Solar
Solar
Wind
Wind
collector collector Onshore Offshore
FP
ET
PV
CSP
Figure 1: Specific aluminium use in the various technologies (per kW heat (solar thermal collectors) or
kW electricity (others); FP: flat-plate, ET: Evacuated tube)
For solar thermal collectors (flat-plate and evacuated tube collectors), aluminium is mainly
used in absorbers, casings and frames. Studies support the trend of increased aluminium
use in absorbers. Out of 289 systems analyzed 34% use aluminium absorbers.
The market sales of aluminium could increase if specific aluminium use moved from “Al
moderate” with 3.1 kg/m² to “Al maximum” with 4.3 kg/m² (flat-plate) or 0.9 kg/m² to 4.3 kg/m²
for evacuated tube technologies. This can be achieved by replacing copper with aluminium in
absorbers of flat-plate collectors and steel with aluminium in frames in evacuated tube collectors. Additionally, if reflector shields and water tanks are used in evacuated tube collectors
then aluminium use would be even higher. This assumption is part of Al maximum.
In SCENARIO BEST ESTIMATE, which assumes a dynamic market growth from 210 million
m² installed today to 11 billion m² in 2050 and a moderate specific aluminium use, the total
aluminium in use could be 17 million tons (Mt) by 2050. In SCENARIO BEST ESTIMATE
Plus which assumes a move from Al moderate to Al maximum, 39 Mt aluminium could be in
use in 2050.
With wind turbines, steel is the material predominantly used, with about 85% of the total
material input. Aluminium plays a subordinate role and is used in a range from under 0.01%
up to about 2.5 % of the total material input. Today, only a low amount of aluminium, estimated around 0.1 Mt, is used in wind turbines today, primarily in nacelles and rotors.
In SCENARIO BEST ESTIMATE the total aluminium in use increases to 1.2 Mt aluminium by
2050. The shift from Al moderate to Al maximum concerning aluminium use in SCENARIO
BEST ESTIMATE Plus could lead to approximately 7.4 Mt of aluminium in use by 2050. Market sales of aluminium could be increased by replacing the coverings of the wind turbine nacelle and rotors with aluminium.
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Photovoltaic systems (PV) directly convert solar energy into electricity. According to our research, 0.4 Mt of aluminium is used in photovoltaic systems today. Aluminium is predominantly processed in a construction/mounting structure (72% of total aluminium input), followed by input to panel frames (22%), and aluminium use in inverters (6%).
Analysis shows that between 23 kg/kW (Al minimum) and 59 kg/kW (Al maximum) of aluminium are used in photovoltaic systems. In 2050, aluminium use would rise to 19 Mt in
SCENARIO BEST ESTIMATE. SCENARIO BEST ESTIMATE Plus with moderate growth
and Al maximum of 59 kg/kW would lead to 35 Mt 2050. The full market sales potential of
aluminium in photovoltaic systems could unfold if aluminium were used more frequently for
mounting structures and frames.
Solar cookers are devices that generate heat for cooking from sun energy. In the absence
of detailed expansion scenarios only the overall potential of solar cookers was examined.
Aluminium is mainly found in frames and reflectors, but usage varies strongly between 0.1
kg/unit, if no aluminium is used at all (e.g. reflector made of optical polyester and/or wooden
frame), and 20 kg/unit if both frame and reflectors are made of aluminium.
Assuming a moderate specific aluminium use and a moderate overall market sales potential
of 83 million units, SCENARIO BEST ESTIMATE indicates 0.3 Mt aluminium in use in solar
cookers by 2050 if aluminium were used only in reflectors. The SCENARIO BEST
ESTIMATE Plus shows a potential of approximately 1.7 Mt by 2050.
Since frames are made from other materials (mainly steel), a replacement potential is given.
Nevertheless, even if aluminium use is low compared to other technologies, solar cookers
could be a favourable technology on which to focus especially with regard to CDM projects.
As there is no clear trend in which directions material inputs will evolve for solar cookers,
cheap and light systems which are currently not using aluminium should be further observed
in the upcoming years.
Concentrated solar power (CSP) systems use concentrated sunlight to generate electricity
or heat. Today, 33’000 tons of aluminium are installed in CSP technologies. Aluminium is
mainly used in parts of the power block and the cooling tower, while system frames are
mainly made of steel and the absorber system does not use aluminium.
Recently, only small amounts of aluminium have been used. According to SCENARIO BEST
ESTIMATE the total aluminium in use increases to 51 Mt by 2050. SCENARIO BEST
ESTIMATE Plus indicates a total aluminium use of 105 Mt if specific aluminium use rises
from 65 kg/kW to 131 kg/kW (shift from Al moderate to Al maximum). The market sales potential of aluminium could be maximized if elevation and collectors, which are today mostly
made of glass and steel, were replaced by aluminium.
In 2050 the total aluminium invested in renewable energy systems could amount to 88
Mt in SCENARIO BEST ESTIMATE where specific aluminium use and expansion path are
based on moderate assumptions (see Table 1 and Figure 2; for more details see Table 53).
SCENARIO BEST ESTIMATE Plus even indicates 188 Mt if specific aluminium use is maximized according to above mentioned aluminium replacement potentials for single renewable
energy systems (Al moderate  Al maximum).
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Mt Aluminium
500
SCENARIO HIGH
400
SCENARIO BEST
ESTIMATE Plus
300
SCENARIO BEST
ESTIMATE
200
SCENARIO BEST
ESTIMATE Minus
100
SCENARIO LOW
0
2020
2030
2040
2050
Figure 2: Projected cumulative aluminium used in renewable energy systems
Table 1: Study results in brief
Use in renewable energy systems in million tons (Mt)
Global expansion of Renewable Energy Systems
Cumulative
aluminium use
in 2050
Annual use of
aluminium in
2031 to 2050
Al Minimum
PATH LOW
PATH BEST
ESTIMATE
4
15
Al Moderate
88
Al Maximum
188
Al Minimum
PATH HIGH
470
0.6
0.08
Al Moderate
3.3
Al Maximum
8.8
16.3
In Figure 3, projected annual aluminium sales for all focus renewable energy systems are
shown for the SCENARIO BEST ESTIMATE. The total annual aluminium sales increase
steadily. From now until the year 2020, approximately 0.5 Mt/a or 1.4 percent of annual aluminium production could be used in renewable energy systems every year. From 2021 until
2030, total annual aluminium sales for renewable energy systems could increase to around
1.5 Mt or four percent of annual aluminium production and from 2031 until 2050 sales could
increase to 3.3 Mt or nearly 9 percent of annual aluminium production.
As Figure 3 shows, in SCENARIO BEST ESTIMATE solar-based technologies (CSP, PV and
solar thermal collectors) account for most of the overall potential. Moreover, in SCENARIO
BEST ESTIMATE Plus, the rise of aluminium use from Al moderate to Al maximum in CSP,
solar thermal collectors and PV systems seems to be very promising.
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Mt/a
% of annual
aluminium production
9,0
8,0
20
7,0
6,0
15
5,0
4,0
Wind turbines
10
Photovoltaic
systems
5
CSP
3,0
2,0
Solar thermal
collectors
1,0
0,0
0
today-2020
2021-2030
2031-2050
Figure 3: Projected annual aluminium use in renewable energy systems in the SCENARIO BEST
ESTIMATE
If aluminium use could be further maximized according to SCENARIO BEST ESTIMATE Plus
(shift: AL moderate  Al maximum), the same installation rates could lead to even higher
numbers; e.g. 8.8 Mt/a from 2031-2050 (see Figure 4 and for further details Table 52).
Mt/a
% of annual
aluminium production
9,0
8,0
7,0
20
Solar thermal
collectors
15
Wind turbines
10
Photovoltaic
systems
6,0
5,0
4,0
3,0
2,0
5
CSP
1,0
0,0
0
today-2020
2021-2030
2031-2050
Figure 4: Projected annual aluminium use in renewable energy systems in the SCENARIO BEST
ESTIMATE Plus
By 2050 the final energy supply of the selected technologies could amount to around 9’800
TWh electricity and 6’600 TWh heat according to SCENARIO BEST ESTIMATE. In comparison, total global electricity generation in 2007 was 19’771 TWh. Total CO2 abatement potential in SCENARIO BEST ESTIMATE would be around 9’300 Mt in 2050 compared to
marginal technologies (gas and coal electricity generation and gas/oil heating systems). As
comparison: The annual emitted CO2 emissions in 2007 were approximately 29’000 Mt of
CO2.
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In conclusion, renewable energy technologies offer a large market opportunity for aluminium. In the best estimate scenario, renewable energy technologies would introduce a market
increase of up to 10 % additional aluminium use. This is due to:

the large area of energy collection (e. g. module or collector surface)

the requirement of solar-directed installation (e. g. mounting and frames of solar
power plants)

the expected dynamic market development (high expansion targets in many countries).
In many technologies (e.g. PV and solar collectors), aluminium use is increasing, while in
others (e. g. for solar thermal power plants) materials such as steel and glass are predominantly used.
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Content Executive summary................................................................................................................ 2 1 Introduction ....................................................................................................................... 10 2 Methodological approach ................................................................................................. 12 3 Aluminium in individual renewable energy systems ..................................................... 16 3.1 Solar thermal collectors for hot water generation and process energy ............................ 16 3.1.1 Description of technologies
16 3.1.2 Current market situation for solar thermal collectors
18 3.1.3 Specific aluminium use in solar thermal collectors
23 3.1.4 Technology scenarios for solar thermal collectors
27 3.1.5 Resulting current and future aluminium use in solar collectors
30 3.2 Wind turbines ................................................................................................................... 32 3.2.1 Description of technologies
32 3.2.2 Current market situation for large wind turbine systems
33 3.2.3 Specific aluminium use in wind turbine systems
36 3.2.4 Technology scenarios for wind turbines
42 3.2.5 Resulting current and future aluminium use in wind turbine systems
45 3.2.6 Cables and wind turbines (excursion)
47 3.3 Photovoltaic sytems ......................................................................................................... 48 3.3.1 Description of technologies
48 3.3.2 Current market situation for photovoltaic systems
48 3.3.3 Specific use of aluminium in photovoltaic systems
51 3.3.4 Technology scenarios for photovoltaic systems
55 3.3.5 Resulting current and future aluminium use in photovoltaic sytems
57 3.4 Solar cookers ................................................................................................................... 60 3.4.1 Description of technologies
60 3.4.2 Current market situation for solar cookers
62 3.4.3 Specific aluminium use in solar cookers
64 3.4.4 Technology scenarios for solar cookers
66 3.4.5 Resulting current and future aluminium use in solar cookers
68 3.4.6 Solar community kitchens (excursion)
69 3.5 Concentrating Solar (Thermal) Power (CSP) ................................................................... 71 3.5.1 Description of technologies
71 3.5.2 Current market situation for CSP
74 3.5.3 Specific aluminium use in CSP technologies
76 3.5.4 Technology scenarios for Concentrated Solar Thermal Power
80 3.5.5 Resulting current and future aluminium use in CSP
83 3.6 Cables used in focus REn technologies: excursion ......................................................... 88 4 Overall potential of aluminium ......................................................................................... 91 4.1 Summary of specific aluminium use in renewable energy systems ................................. 91 4.2 Overall use of aluminium in renewable energy systems .................................................. 94 5 Bibliography .................................................................................................................... 100 8
Aluminium and Renewable Energy Systems
IFEU
6 Annex ............................................................................................................................... 107 6.1 Detailed results............................................................................................................... 107 9
Aluminium and Renewable Energy Systems
IFEU
1 Introduction
The addition of renewable energy sources to the global energy mix has emerged as one of
the most important changes within the energy sector over the last decade. Today, renewable
energy sources in the form of wind, solar, hydropower, geothermal, and biomass provide a
significant amount of energy, namely electricity and heat. Renewable energy systems have
the potential to play an important part in a low carbon future since they generate energy with
very low greenhouse gas emissions and global dependence on fossil resources.
With the demand for energy and in particular renewable energy expected to rise in the future,
the study “Aluminium and Renewable Energy Systems – Prospects for the sustainable generation of electricity and heat” was commissioned by the International Aluminium Institute.
This was done in order to provide information on the present and future potential use of aluminium in selected renewable energy systems as well as on energetic and environmental
benefits, namely generated energy and CO2 reduction potential, for the reference years
2020, 2030, and 2050.
The following renewable energy systems have been focused on:
-
solar thermal collectors for hot water generation and process energy
small and large wind turbines
photovoltaic systems
solar cookers
concentrating solar thermal power plants, based on reflector systems for electricity
generation.
Flat-plate collectors
Photovoltaic systems
Evacuated tube collectors
Wind turbines
Solar cookers
CSP
Figure 5: Renewable energy systems in focus
In order to identify the potential of aluminium in renewable energy systems, it is necessary to
set out a methodological approach, described in chapter 2, that can be applied to renewable
energy systems under consideration. In chapter 3 the individual renewable energy systems
are analyzed.
Renewable energy systems chapters are structured similarly: the description of the specific
technology (chapter x.x.1), an overview of the current market situation (chapter x.x.2), an
analysis of the specific aluminium use (chapter x.x.3) as well as the technology specific expansion scenarios (chapter x.x.4). Every specific technology chapter concludes with results
on current and future aluminium use for renewable energy systems for reference years and
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energetic and environmental benefits of renewable energy systems using aluminium (chapter
x.x.5)1. Chapter 4 summarizes the overall potential of aluminium.
1
Energetic benefits for solar cookers are not calculated.
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2 Methodological approach
The total amount of aluminium that is processed in renewable energy systems as well as the
CO2 abatement potential of renewable energy technologies that use aluminium as a key
component need to be scientifically estimated. Therefore, it is necessary to set out a methodological approach that can be applied to all focus technologies in the same way2.
As aluminium’s role today as well as its future market sales potential in the years 2020, 2030
and 2050 needs to be regarded, it is also necessary to gather information on the present and
future deployment of technologies. Thus, time is the underlying factor and therefore the total
amount of aluminium used and its CO2 abatement potential needs to be calculated separately for given effective dates, namely for today, 2020, 2030 and 2050.
Methodological steps
Firstly, to estimate the total amount of aluminium used for REn technologies at a given time
T, the specific aluminium use for renewable energy systems needs to be calculated.
Therefore, the total amount of aluminium in kg and rated power in kW for technologies must
be identified. Various life cycle analysis and studies were examined and interviews held with
manufacturers and product designers (see Table 3 and Table 4).
It should be noted that this study cannot cover all sub-types of specific technologies. Thus,
reference technologies have to be defined for specific renewable energy systems. There will
be three reference technology systems for every single specific renewable energy system:
Al minimum: a reference technology with minimum specific aluminium use, according to
LCA studies examined and manufacturer’s information.
Al moderate: a reference technology with moderate specific aluminium use.
Al maximum: a reference technology with maximum specific use of aluminium, if aluminium
is used to a broader extent (e.g. aluminium replaces competing materials).
Secondly, the global (installed) capacity of the researched renewable energy systems
needs to be identified. Thus various renewable energy expansion scenarios for single technologies are investigated in order to determine the installed capacities today and estimated
development paths in the future. Out of these examined scenarios, three expansion scenarios are defined:
PATH LOW: pessimistic expansion path for researched renewable energy systems.
PATH BEST ESTIMATE: moderate expansion assumed to model a scenario with high probability.
PATH HIGH: optimistic expansion path for researched renewable energy systems.
2
As discussed later, the application of the methodology deviates slightly in regard of solar thermal collectors. For an explanation see chapter 3.1.4.
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Thirdly, the total amount of aluminium used in specific renewable energy systems can be
derived by multiplying the expected installed capacity and the specific aluminium use:
Total amount of aluminium used in Renewable Energy System
=
Global installed capacity
*
Specific aluminium use
This study will determine total amounts of aluminium by combining these pathways to the
scenarios according to Table 2. For example, the total amounts of aluminium for a given time
for SCENARIO BEST ESTIMATE will be calculated by multiplying a moderate specific aluminium use for the reference technology (Al moderate) with minimal moderate installed capacity estimate (= PATH BEST ESTIMATE) for a certain reference year.
Table 2: Scenario definition3
Scenario
Specific aluminium use
Technology Diffusion scenario
SCENARIO LOW
Al minimum
PATH LOW
SCENARIO BEST ESTIMATE Minus
Al minimum
PATH BEST ESTIMATE
SCENARIO BEST ESTIMATE
Al moderate
PATH BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
Al maximum
PATH BEST ESTIMATE
SCENARIO HIGH
Al maximum
PATH HIGH
Finally, in order to calculate CO2 abatement potential of renewable energy systems in which
aluminium is used full load hours for those technologies and a technology-specific substitute
factor need to be defined. This substitution factor determines the average CO2 mitigated per
kWh of final energy supplied. Technology specific definitions are indicated in the technology
chapters.
According to the three paths (LOW, BEST ESTIMATE, HIGH), CO2 abatement potentials for
every single renewable energy systems will be calculated for the reference years4.
3
Colors for scenarios will be used throughout the text in order to enhance readability.
Explanation on chosen CO2 substitution factors for renewable energy technologies is given in specific technology chapters.
4
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Table 3: Technology scenarios examined
Scenarios examined
EUROPEAN PHOTOVOLTAIC INDUSTRY ASSOCIATION, EPIA (ed.) (2007): Solar Generation IV – 2007: Solar electricity for over one billion people and two million jobs by 2020. Amsterdam, The Netherlands.
EUROPEAN WIND ASSOCIATION, EWEA (ed.) (2009): The economics of wind. Brussels, Belgium.
GLOBAL WIND ENERGY COUNCIL, GWEC/GREENPEACE (ed.) (2008): Global Wind Energy Outlook 2008.
Brussels, Belgium/Amsterdam, The Netherlands.
GREENPEACE (2009): Sauberer Wüstenstrom: Globaler Ausblick auf die Entwicklung solarthermischer
Kraftwerke 2009. Amsterdam, The Netherlands.
GREENPEACE (ed.) (2007): Solar Generation IV – 2007: Solar electricity for over one billion people and
two million jobs by 2020. Amsterdam, The Netherlands.
GREENPEACE (ed.) (2008): Energy [r]evolution: a sustainable global energy outlook. Amsterdam, The
Netherlands.
IEA (ed.) (2008a): Energy Technology Perspectives 2008 – Scenarios & Strategies to 2050. Paris,
France.
MAJOR ECONOMIES FORUM, MEF (ed.) (2009): Technology Action Plan: Solar Energy, Report to the
Major Economies Forum on Energy and Climate. Washington D.C., USA.
PETER, S. / LEHMANN, H. (2007): Renewable Energy Outlook: Energy Watch Group Global Renewable
Energy Scenarios. Markkleeberg, Germany.
SHELL (ed.) (2008): Shell Energy scenarios to 2050. The Hague. The Netherlands.
UMWELTBUNDESAMT (ed.) (2007): Zukunftsmarkt solarthermische Stromerzeugung. Dessau, Germany.
VIEBAHN, P. (2008): NEEDS - Final report on technical data, costs, and life cycle inventories of solar
thermal power plants. Stuttgart, Germany.
WEIß, W. /BERGMANN, I./STELZER, G. (2009): Solar Heat Worldwide: Markets and contribution to the
energy supply 2007. Gleisdorf, Austria.
WORLD ECONOMIC FORUM (ed.) (2009): Task Force on Low-Carbon Prosperity: Recommendations October 2009. Geneva, Switzerland.
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Table 4: LCAs examined (selection)
LCAs examined
EUROPEAN COMMISSION (ed.) (2009): Environmental and ecological life cycle inventories for present
and future power systems in Europe (ECLIPSE): Life Cycle Inventories. Brussels, Belgium.
JUNGBLUTH, N. (2009): Ecoinvent - Teil XII: Photovoltaics. Dübendorf, Switzerland.
NEW ENERGY EXTERNALITIES DEVELOPMENTS
Inventory Database. -,-.
FOR
SUSTAINABILITY, NEEDS (ed.) (2009): Life Cycle
JUNGBLUTH, N. (2007): Ecoinvent -Teil XI: Solarkollektoranlagen. Dübendorf, Switzerland.
BAUER, B. / BAUER, C. (2007): Ecoinvent - Teil XIII: Windkraft. Villingen, Switzerland.
EUROPEAN COMMISSION (ed.) (2009): Environmental and ecological life cycle inventories for present
and future power systems in Europe (ECLIPSE): Life Cycle Inventories. Brussels, Belgium.
VESTAS (2006a): Life cycle assessment of electricity produced from onshore sited wind power plants
based on Vestas V82
VESTAS (2006b): Life cycle assessment of offshore and onshore wind power plants based on Vestas
V90
ELSAM ENGENEERING (2004): Life Cycle Assessment of offshore and onshore sited wind farms.
Fredericia, Denmark.
BAUER, B. / BAUER, C. (2007): Ecoinvent - Teil XIII: Windkraft. Villingen, Switzerland.
DONG ENERGY (ed.) (2008): NEEDS - Final report on offshore wind technology. Hamburg, Germany.
ANGERER, G./ERDMANN, L./MARSCHEIDER-WEIDEMANN, F./SCHARP, M./LÜLLMANN, A./ HANDKE, V./
MARWEDE, M. (2009): Rohstoffe für Zukunftstechnologien: Einfluss des branchenspezifischen Rohstoffbedarfs in rohstoffintensiven Zukunftstechnologien auf die zukünftige Rohstoffnachfrage.
Karlsruhe, Germany.
LEHMANN, H./REETZ, T./ROEWER, S./LIEDTKE, C. (2008): Ökologische Chancen und Risiken großtechnisch angelegter solarthermischer Kraftwerke. Wuppertal, Germany.
VIEBAHN, P. (2004) :SOKRATES-Projekt - Solarthermische Kraftwerkstechnologie für den Schutz des
Erdklimas. Stuttgart, Germany.
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3 Aluminium in individual renewable energy systems
This study will focus on the following renewable energy systems which are examined in detail
in the following chapters:
-
solar thermal collectors for hot water generation and process energy (chapter 3.1)
small and large wind turbines (chapter 3.2)
photovoltaic systems (chapter 3.3)
solar cookers (chapter 3.4)
concentrating solar thermal power plants, based on reflector systems for electricity
generation (chapter 3.5).
3.1 Solar thermal collectors for hot water generation and process energy
Solar thermal collectors transform sun rays into thermal energy. The resulting heat is mainly
used for hot water generation, space heating, process heat and the generation of electricity.
Depending on the desired level of temperature and further criteria (e.g. available space, seasonal climate fluctuations), different technologies are employed.
3.1.1 Description of technologies
Unglazed plastic collectors are basic solar plastic absorbers without coping that are assembled simply (see Figure 6) and provide low cost heat. Concerning temperature, the range of
use is between 20 and 40°Celsius (stagnation temperature: approx. 90°Celsius; maximum
temperature to be reached if no heat is conducted by the solar thermal collector). Unglazed
plastic collectors are predominantly used for hay drying and public bath heating. For the latter the circulation of the filter is completed by a collector field. For hay drying the air flow is directed through the absorber and thereafter into the hay storage facility.
Figure 6: Unglazed solar thermal collector made of plastic (example)
Flat-plate collectors have a glass coping (see Figure 7). They warm up the heat transfer medium within a range of use of 30 up to 100°C (stagnation temperature: approx. 200°C). In
comparison to unglazed collectors, the higher level of temperature is due to the reduction of
convective and radiative heat transfer losses by the glass coping. Flat-plate collectors are
used for hot water generation and space heating.
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Figure 7: Example of a flat-plate solar thermal collector5
In evacuated tube collectors the absorber plate is located within an air-evacuated glass tube.
Therefore, convective and conductive losses of heat are suppressed (see Figure 8). The
temperature of the heat carrying fluid is between 40 and 150°C (stagnation temperature:
approx. 300°C). The radiation received in evacuated tube collectors can be exploited to a
higher degree compared to flat-plate collectors.
Figure 8: Principle of an evacuated tube collector with heat pipe; view from top6
It must be noted that evacuated tube collectors appear in many different forms: a) systems
with or without a reflector shield depending on the absorber characteristics, b) systems with a
(manifold) casing or an on-top water tank, and c) mixed variations of a) and b).
Figure 9: Evacuated tube collector with (manifold) casing; without reflector shield and without water
tank7
5
Source: Elfsecsolar.
6 Source: Quaschning (2004): Solar thermal water heating: Technology Fundamentals. In:
http://www.jxj.com/magsandj/rew/index.html , 02/2004: pp. 95-99.
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Figure 10: Evacuated tube collector with water tank and reflector shield8
3.1.2 Current market situation for solar thermal collectors
Current solar thermal collectors for hot water generation and process heat are unglazed collectors, flat plate collectors, and evacuated tube collectors. As shown by Solar Heat Worldwide report, which was prepared within the framework of the Solar Heating and Cooling Programme (SHC) of the International Energy Agency (IEA), at the end of 2007 the solar thermal collector capacity in operation worldwide was approximately 147 GWth9,10. This corresponds to about 210 million square meters of collector panels installed. The Renewables
Global Status Report supports the overall Solar Heat Worldwide figure of 147 GWth. It further
estimates that existing solar hot water and heating capacity has increased by 15 percent in
2008 and has doubled in capacity compared to 200411.
Due to the fact that the Solar Heat Worldwide report fully concentrates on solar thermal collectors, including their spatial distribution and technical differences, it illustrates the current
market situation in depth. Consequently, its figures are taken as reference for today’s installed solar thermal collector capacity.
Installed capacity by technology
The distribution of worldwide capacity in operation varies widely by collector type: Evacuated
tube collectors have the biggest market share, namely 50%, followed by flat plate collectors
at 33% and unglazed collectors that have a share of 17%. The total capacity in 2007 is divided into 46 GWth glazed flat-plate collectors, 74 GWth evacuated tube collectors and 25
GWth unglazed collectors (see Figure 11)12.
7
Source: Penn Solar Supply.
Kingeagle Solar Energy Industry Co., Ltd.
9
Weiß et al. (2009): p. 15.
10
GWth = Gigawatt thermal.
11
Ren21 (2009): p. 13.
12
ibd.
8
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Aluminium and Renewable Energy Systems
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in GW
80
74
70
60
46
50
40
25
30
20
10
0
Evacuated tube
collectors
Flat plate collectors
Unglazed collectors
Figure 11: Installed capacity of solar thermal solar collector types in GW (Source: Solar Heat Worldwide 2009)
In 2007 evacuated tube collectors were installed on an area encompassing 106 million
square meters. Flat-plate collectors covered 66 million square meters and unglazed collectors 36 million square meters (see Figure 12).
in m²
120
106
100
80
66
60
36
40
20
0
Evacuated tube
collectors
Flat plate collectors
Unglazed collectors
Figure 12: Installed capacity of solar thermal solar collector types in million square meters (Source:
Solar Heat Worldwide 2009)
Installed capacity by regions
Concerning existing capacity China is the world leader with 67% of existing global capacity
(see Figure 13). China is followed by the European Union, which has a 12% share. The
German share needs to be highlighted as solar hot water systems set record growth in 2008,
with over 200’000 systems installed for an increase of 1.5 GWth in capacity. Spain also saw
rapid growth while the rest of Europe, besides Germany, added about 0.5 GWth of new capacity. Among developing countries Brazil, India, Mexico, Morocco, Tunisia, and others saw
an acceleration of solar hot water installations13.
13
Ren21 (2009): p. 13.
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China
67%
Others
6%
Brazil
2%
Israel
3%
Japan
4%
European
Union
12%
Turkey
6%
Figure 13: Share of solar hot water/heating capacity existing, Top 10 countries, 2007 (Source: Renewable Energy Policy Network for the 21st century: Renewables Global Status Report (Update): 13)
Growing markets and market sales potentials for solar thermal collector technologies are to
be found in China, the European Union, Brazil and India (see Table 5). Besides China being
the world leader, concerning existing capacity, it is also the fastest growing market for solar
thermal collector systems. There 16 GWth were added in 2007 alone or an existing capacity
growth of 19%. The European Union added 1.9 GWth or 12%, Brazil 0.3 GWth or 12% and India 0.2 GWth or 13%. The biggest market in the future will be China according to these figures.
Table 5: Solar Hot Water Installed Capacity existing and added 2007
China
European Union
Turkey
Japan
Israel
Brazil
USA
Australia
India
Others
World total
Additions 2007
in GW
Existing 2007
in GW
16.0
1.9
0.7
0.1
0.1
0.3
0.1
0.1
0.2
0.5
20.0
84.0
15.5
21.0
4.9
3.5
2.5
1.7
1.2
1.5
3.6
126.0
Growth rate 2007 in %
19 %
12 %
3%
2%
3%
12 %
5%
8%
13 %
14 %
19 %
Although China is the biggest solar thermal collector producer and at the same time biggest
market in the world, installations of solar hot water systems per capita are still quite low com-
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pared to other countries, meaning there remains a huge market sales potential in the region14.
The United States is another promising market outside Europe; still small but with a high potential for growth. According to the US Solar Energy Industries Association, the US solar
thermal collector market grew by 50% in 2008 reaching some 229’000 m² of collector area,
or around 160 megawatts thermal (MWth)15.
Key manufacturers and market actors
Figure 14 shows that annual sales have been growing steadily in recent years. On a global
scale the solar thermal market is dominated by China, which had a 75% share of global sales
in 2008 and estimated 19’000 megawatts (MW) of annual sales. Germany increased sales
from 672 MW to 1’334 MW and had the second highest sales with 5%. The US had 922 MW
or 4%, Turkey 3% and Australia 2% with no other country having more than 1%. Although
Japan has very high solar PV sales, its sales in solar thermal collector systems are insignificant16.
in GW
30
25
25
20
18
20
13
15
10
9
10
2001
2002
15
12
7
5
0
2000
2003
2004
2005
2006
2007
2008
Figure 14: Annual sales 2000-2008 in MW (Source: ABS Renewable Energy Database)
China has a sophisticated commercial solar thermal collector industry with innumerable factories manufacturing and selling solar systems. The products in China consist mainly of three
types: flat-plate and evacuated tube with and without storage tank.
From a global perspective, China is strongly competing with the European solar thermal collector industry in the global market. Although Chinese technology is currently of lower quality
compared to European technology, it demonstrates a rapid development and is expected
14
Junfeng/ Runqing (2005): pp. 25-27.
Solar Energy Industries Association (2009): p. 8.
16
ABS Energy Research (2010).
15
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that in future Chinese solar-thermal collector systems will be as reliable as the European
17
ones albeit available at lower cost .
In order to identify key manufacturers, technologies (flat-plate collectors and evacuated tube
collectors) need to be distinguished18. At first, flat-plate technology is focused on.
Flat-plate collectors
Among the top solar thermal manufacturers stands Austria’s GREENoneTEC. Annual production capacity from its eight lines was 1’100’000 m² in 2008. Another key solar thermal
manufacturer is TiSUN, also based from Austria. In 2007, TiSUN’s annual production capacity reached up to 150’000 m² of collector surface.
While GREENoneTEC and TiSun are specialized in solar thermal technology, a significant
market force comes from a group of industrial companies which already supply a range of
(renewable) energy solutions, such as condensing boilers, heat pumps and solar PV.
Among the largest of these heating technology companies is Viessmann, one of the world’s
largest solar thermal suppliers. Its annual sales of solar thermal collector systems reach
500’000 m².
Bosch Thermotechnology has also expanded its global production capacity for solar collectors from 250’000 to 350’000 units annually, equivalent to some 800’000 m² of collector surface area.
Schüco International KG from Germany is a leading European building envelope specialist
that develops and markets aluminium and steel product solutions. Experience in aluminium
fabrication and building integration has been used to construct solar collectors made from an
aluminium frame and rear panel. The company has an annual production capacity of some
400’000 solar collectors, equivalent to over 1’000’000 m².
A number of other major players in the solar thermal market are based outside of Europe,
among them Turkey’s Ezinc. One of the major manufacturers of solar thermal components,
Ezinc solar collector production capacity has reached 400’000 m².
Other major manufacturers are Rheem of Australia, and Solahart, a subsidiary of Rheem,
Genersys plc and Solar Twin Ltd of the UK, Spain’s Acciona Energy and Ibersolar Energía,
S.A, Enerworks from Canada and Soletrol, based in Brazil, as well as the Israeli firm Nimrod.
Evacuated tube collectors
It has been estimated that there are approximately 5’000 manufacturers of evacuated tube
collectors worldwide, a sector which is dominated by Chinese companies19.
Himin Solar Energy Group is the world’s largest manufacturer of solar thermal products with
more than 2 million m² of absorber area annually.
Another Chinese based company, Haining Baoguang Heat Collection Tubes Co., Ltd, has
more than 30 automatic production lines. It has the capacity to produce more than
10’000’000 tubes annually.
17
European Commission (2007): p. 4.
Appleyard (2009): pp. 4-12.
19
Appleyard (2009): pp. 4-12.
18
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Beijing Sunda Solar Energy Technology Co., Ltd. is another Chinese manufacturer of evacuated tube solar collectors. Jointly founded by Daimler-Benz Aerospace (DASA) and SUNPU
in 1995, Sunda has been active in the European market for over 12 years and established a
subsidiary in Germany in 1997. The subsidiary followed the 1996 opening of a manufacturing
plant located in Sunhe, Hebei Province, near Beijing which has a production facility of more
than 500’000 tubes per year. More than 60% of the company’s products are sold overseas.
Alongside major solar players such as GREENoneTEC and Viessmann Werke, the largest
assemblers for evacuated tube collectors in Europe are Germany’s Ritter Solar and Kingspan Thermomax of the UK.
3.1.3 Specific aluminium use in solar thermal collectors
The current specific use of aluminium is identified for both reference technologies (flat-plate
and evacuated tube collectors) separately.
Flat-plate collectors
Flat-plate collectors consist primarily of the following key components: absorber, frame, and
casing (see Figure 15). In those, different materials can be used. Materials used in absorbers
are copper, aluminium and steel. Frames and casings are mostly made of aluminium and
steel; to a marginal extent wood is used.
As the reference for flat-plate collectors, a typical product has been chosen20.
Figure 15: Flat-plate collector and main components21
The reference flat-plate collector has a gross area of 3.12 m² and an absorber area of 2.75
m² with an overall weight of 52 kg. A detailed overview of aluminium use is given in Table 6.
The absorber consists of 4.9 kg copper with no aluminium to be found; a 0.2 mm thick copper sheet is used22. The frame contains around 6 kg aluminium (1.8 mm thick aluminium
sheet). The casing is made of 3.8 kg aluminium (0.5 mm thick aluminium sheet). Aluminium,
in frames and casings, is predominantly used because the material is lighter which is prefer-
20
Interview with Mr Cabarrubia, director of production, Soltop Schuppisser AG, 29 April 2010.
21
22
Source: Skyflair.
Figures are rounded throughout the text in order to enhance readability.
23
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able for installation23. For the balance of plant (BOP) only the water heat storage is regarded
as it is the main component of BOP. According to experts24, the average water heat storage
with a 200 liter capacity, an integrated container and a heat exchanger consists of steel (St
37) and chromium-nickel-steel weighing 170 kg. The only component that contains aluminium is an aluminium foil for heat containment25.
In total around 9.8 kg overall weight or around 3.1 kg per m² can be found in this reference
object. This is the moderate amount of aluminium to be found (Al moderate).
Additional aluminium could be used in the absorber component. Aluminium is likely to replace copper, if prices for copper increase steadily26. Studies on materials used in absorbers
support the trend of increasing aluminium use in absorbers27. Furthermore, in order to have
the same conductivity, aluminium needs to be thicker28. Out of 289 systems analyzed 34 percent apply aluminium absorbers; 53 percent use copper and 13 percent other materials (e.g.
glass, steel etc.) (see Figure 16)29.
In the heat storage, additional aluminium use is not very likely as steel is easier to process,
especially for welding, and is cheaper30. Aluminium also corrodes more quickly than steel.
Copper
53%
Others
13%
Aluminium
34%
Figure 16: Materials used in flat plate absorbers
In the reference technology 0.2 mm thick copper, totalling 4.9 kg, is used. If aluminium replaces copper in this component, it has to be 0.5 mm thick in order to have the same thermal
conductivity characteristics as copper31, resulting in 3.7 kg aluminium per absorber. If aluminium is used in an absorber as an alternative material to copper the total weight of aluminium
will then be 13.5 kg, which is equal to 4.3 kg/m² (Al maximum) (see Table 6).
If aluminium is only used to a minimal extent (e.g. absorber made of copper, casing and
frame made of wood), it is assumed that 0.1 kg aluminium is used per square meter (e.g.
screws, bolts etc.) (Al minimum).
23
Interview with Mr Cabarrubia, director of production, Soltop Schuppisser AG, 29 April 2010.
Interview with Mr Hoffmann, Jenni Energietechnik, 6 July 2010.
25
Interview with Bernd Sitzmann, Consolar AG, 13. July 2010.
26
ibd.
27
Meyer (2009): pp. 42-44.
28
Interview with Mr Thole, Schüco International, February 2010.
29
Becker (2010): pp. 67 - 83.
30
Interview with Mr Hoffmann, Jenni Energietechnik, 6 July 2010.
31
Personal communication with Mr Thole, Schüco International, February 2010.
24
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Aluminium and Renewable Energy Systems
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Table 6: Use of aluminium in the flat-plate solar thermal collectors: per component (in kg) and in total
(in kg per square meter)32
Al minimum
Al moderate
Al maximum
Absorber
-
0.0 kg
3.71 kg
Frame
-
5.95 kg
5.95 kg
(Manifold) Casing
-
3.8 kg
3.8 kg
Balance of plant
-
0.0 kg
0.0 kg
Total in kg
Total in kg/m²
34
0.1kg/m²
33
9.75 kg
13.46 kg
3.1 kg/m²
4.3 kg/m²
Evacuated tube solar thermal collectors
A common, market-available evacuated tube collector without a water tank and without a reflector shield serves as a basic reference system (see Figure 17). Main components are absorber, frame, heat pipes, header pipe and (manifold) casing. To take into account the whole
spectrum of this technology, the components water tank and reflector shield are additionally
included in analysis for estimates of Al maximum.
The basic reference technology consists of 30 tubes, each with a tube height of 1’800 mm
and 47 mm diameter. The total absorber area is 2.4 m², the gross area is 4.36 m². Its overall
weight is 94.8 kg.
Absorbers consist mainly of aluminium or copper. In this reference technology, 0.2 mm thick
aluminium fins are used, which total 1.3 kg aluminium within the absorbers. Aluminium is
used less frequently than copper, but will be used more widely in the future35.
The frame is made of a 1.5 mm thick stainless steel sheet (8.1 kg), but can easily be replaced by aluminium36. Both aluminium and stainless steel are easily available in local markets and possess good potential for being used in solar water heating. Aluminium however
has a distinctive advantage over steel as aluminium is lighter37. The (conservative) estimate
for the replacement potential of aluminium is 2.8 kg, if 1.5 mm thick aluminium is used instead of a 1.5 mm thick steel sheet.
32
Colors indicate: yellow: moderate amount of aluminium used; green: maximum amount of aluminium
used, if aluminium replaces other materials in components; red: minimal amount of aluminium used.
33
Interview with Mr Cabarrubia, director of production, Soltop Schuppisser AG, 29 April 2010.
34
Related to gross area (3.12m²).
35
Bärbel (2008): pp. 68-77.
36
Interview with Mr Roinson, Europe Managing Director, Apricus Solar, 11 June 2010 at Intersolar Fair
Munich.
37
Asif, M. (2007): pp. 337-346.
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Aluminium and Renewable Energy Systems
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Figure 17: Evacuated tube collector: basic reference technology38
The (manifold) casing can be made of steel but here it is made of aluminium (2.6 kg aluminium). Header pipe in the reference technology consists of copper (1.4 kg). As aluminium is
also used for header pipes the replacement potential for aluminium can be estimated to account for 0.4 kg per header pipe (conservative estimate if aluminium replaces copper, assuming only equal material thickness).
Heat pipes are made of 0.7 mm thick copper sheet in the reference technology (0.3 kg), but
can be replaced by aluminium (0.12 kg).
Systems with water tanks are very common in China and developing countries. According to
experts from Chinese manufacturers, water tanks consist of an inner and outer tank and are
mostly made of steel to prevent corrosion and because it is cheaper39. In water tanks
stainless steel can be replaced by aluminium. But it is recommended to only replace the steel
in the outer tank as the inner tank material is permanently in contact with water40. The reference technology is a Sunstar 200 liter water tank made of 1.2 mm thick steel. If aluminium
replaces this competing material, 4.2 kg aluminium could be processed, additionally.
If a shield reflector is also used the material might be aluminium. The aluminium use for a
reference reflector shield41 is assumed to be 3.9 kg42. It is assumed that the average solar
thermal collector needs a reflector that weighs 1.8 kg, resulting in 3.9 kg of extra aluminium
use (see Table 7).
38
Source: Apricus.
Interview with Ms Qiu, Sales manager, Hejiasun, 11 June 2010 at Intersolar Fair Munich;Interview
with Mr Horace, Trade Department, Sangle Solar, 11 June 2010 at Intersolar Fair Munich; Interviwe
with Mr Xu, Sales Manager, Sidite Solar Water Heater, 11 June 2010 at Intersolar Fair Munich.
40
Interview with Mr Vasiliadis, Export Department, Nobel Solar Innovations, 11 June2010 at Intersolar
Fair Munich.
41
Reference technology Greenonetec VRK 14: Double-ply reflector shield made of 0.3mm thick aluminium sheet, gross area: 2.57m², 7.47kg aluminium overall. Interview with Mr Kohlenbein, Sales,
Greenonetec, 14 June 2010 and Information from Mr Glombitza, Key Account Manager Deutschland,
Greenonetec, 15 June 2010.
42
Calculations: 1) Aluminium demand for reflector shield in reference technology Greenonetec VRK
14: AL demand per m²: 0.3 mm*2,7 g/cm³*2 (double-ply) = 1.62 kg/m²; aluminium demand in kg: 1.62
kg/m²*2.57 m² = 4.16 kg. 2) Aluminium demand carried over from VRK 14 to study’s reference technology: 1.62 kg/m² * 4.36 m² (gross area of study’s gross area) = 3.89 kg.
39
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Table 7: Use of aluminium in evacuated tube solar thermal collectors: per component (in kg) and in total in kg/m²
Al minimum
Al moderate
Al maximum
Absorber
-
1.30 kg
1.30 kg
Frame
-
0.0 kg
2.79 kg
(manifold) casing
-
2.64 kg
2.64 kg
Header pipe
-
0.0 kg
0.42 kg
Balance of
plant
Water tank
-
0.0 kg
4.21 kg
Reflector
-
0.0 kg
7.06 kg
-
0.0 kg
0.12 kg
-
3.94 kg
18.54 kg
0.1 kg/m²
0.9 kg/m²
4.3 kg/m²
Heat pipes
Total in kg
Total in kg/m²
43
The basic reference technology without a reflector shield and without a water tank contains
an overall aluminium specific weight of 3.9 kg of aluminium or 0.9 kg/m² aluminium (Al moderate). If the replacement potential of aluminium is fully tapped by utilizing aluminium in the
frame, reflector, heat pipe and water tank, 18.5 kg or 4.3 kg/m² of aluminium are processed
(Al maximum). If aluminium is only used to a minimal extent it is assumed that 0.1 kg/m²
aluminium is used (e.g. screws, bolts etc.) (Al minimum).
To convert the specific aluminium use per m2 into kg/kW, a conversion factor is needed. As
figures for specific aluminium use in solar thermal collectors are given in kg/m² and not in
kg/kW, figures need to be converted to calculate the global aluminium use for installed technologies. Installed solar thermal systems are measured in terms of collector area (square
meters) rather than in terms of installed capacity. In 2004 the International Energy Agency’s
Solar Heating and Cooling Programme (IEA SHC) and several major solar thermal trade associations agreed on a conversion factor representing a globally averaged yield factor. Accordingly, the installed capacity [kWth] shall be calculated by multiplying the solar collector
area [m²] by the conversion factor 0.7 [kWth/m²]. This factor shall be used for all types of solar
thermal collectors.
3.1.4 Technology scenarios for solar thermal collectors
For the determination of the future development of solar thermal collectors, different technology scenarios were examined (see Figure 18).
43
Related to gross area (4.36 m²).
27
Aluminium and Renewable Energy Systems
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in GW
14'000
Greenpeace (2008),
high
Greenpeace (2008),
low
Peter/Lehmann (2007),
high
Peter/Lehmann (2007),
low
MEF (2009), high
12'000
10'000
8'000
6'000
4'000
MEF (2009), low
2'000
Shell (2008)
'0
today
2020
2030
2040
2050
Figure 18: Solar thermal collector scenarios: Installed capacity in GW today, 2020, 2030, 2050
To show the course that the development of solar thermal collectors will take an upper/maximum and lower/minimum path boundary for expansion scenarios has to be defined,
starting at 147 GWth today. PATH LOW is orientated along the lowest figures for the reference years (here: Greenpeace (2008), low scenario). This scenario assumes low progress
only (business as usual scenario). PATH HIGH reclines to MEF (2008), high figures for 2020
and 2030 and to Greenpeace (2008), high for reference year 2050). This scenario is based
on a best policy approach, assuming dynamically rising energy prices and an increased implementation of collectors worldwide. PATH BEST ESTIMATE shows an alternative path of
expansion, based on own assumptions:
Between 2004 and 2007 the installed capacity of solar thermal collectors increased by approximately 50%. Thus, an increase of approximately 14.5% per year occurs. The Renewables Global Status Report supports this assumption as it states an annual growth rate of
15 % for the years 2007 to 200844.
Assuming that this trend persists, the hypothesis concerning a PATH BEST ESTIMATE is
that an annual increase of around 15% will be in effect until 2020. From 2021, as the market
for solar thermal collectors will become more saturated, increase will assumingly slow down
to an annual rate of 10% until 2030. From 2031 to 2040, the rate drops to an annual rate of
8%, from 2041 until 2050 an annual rate of 5% comes into effect. The three PATHS are outlined in Figure 19.
44
Ren21 (2009): p. 13.
28
Aluminium and Renewable Energy Systems
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in GW
15'000
Path HIGH
10'000
Path BEST ESTIMATE
5'000
Path LOW
'0
today
2020
2030
2040
2050
Figure 19: Solar collector development in PATH LOW, PATH BEST ESTIMATE, PATH HIGH
As for the share of solar collector technologies in the future, market shares are assumed to
be constant for all reference years because no clear indication for variation in distribution of
market share could be found during analysis.
Table 8: Figures used for calculations
Scenarios
Defined specific aluminium use
SCENARIO LOW
Flat-plate
collectors
0.1 kg/m²
Evacuated tube
collectors
0.1 kg/m²
SCENARIO BEST ESTIMATE
3.1 kg/m²
0.9 kg/m²
SCENARIO HIGH
4.3 kg/m²
4.3 kg/m²
Defined technology
expansion PATHs
2020: 360 GW
2030: 640 GW
2050: 1’200 GW
2020: 852 GW
2030: 2’210 GW
2050: 7’770 GW
2020: 3’000 GW
2030: 6’000 GW
2050: 13’680 GW
NOTE: As figures for specific aluminium use are given in kg/m² and not in kg/kW, figures need to be converted to calculate the
global aluminium use for installed technologies. Therefore, calculation is as following: Step 1: Figure from scenario in
GW * 1’000’000 / 0,7 kW/m² = Total area installed. Step 2: Total installed area * market share in percent of subtechnology = Total area installed of sub-technology. Step 3: Total area installed of sub-technology * specific aluminium
use in kg/m² = Total amount of AL used for technology
Based on these capacity developments, heat generation and CO2 mitigation by solar collectors can be calculated. In order to do this the capacities have to be multiplied with full-load
hours. A full-load hour is an hour in which a renewable energy technology produces at full
capacity. 850 h/a for solar thermal collectors are assumed as a global average (Source: personal contact information with regard to newest IPPC study; will be published end
2010/beginning 2011).
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Table 9: Heat generated by solar thermal collectors (in TWh, rounded)
in TWh
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
2020
300
700
2‘600
2030
540
1‘900
5‘100
2050
1‘000
6‘600
11‘600
The CO2 abatement potential for solar thermal collectors can be determined by multiplying
energy production in TWh with a CO2 substitution factor. According to the German Federal
Ministry of Environment, a substitution factor of 0.218 kg CO2/kWh is assumed for Germany
where mainly gas and oil and to a lesser extent hard coal and lignite are replaced45. As no
global substitution factor exists, it is assumed that the primary energy mix in other countries
relies on oil to a broader extent. As oil has a higher CO2 emission factor as gas for example,
the substitution factor in this study is assumed to be 0.3 kg CO2/kWh.
Results are shown in Table 10. In SCENARIO HIGH 3’500 Mt would be saved in 2050. Even
in SCENARIO BEST ESTIMATE 2’000 Mt would be saved by solar thermal collectors. To
compare, in 2007 28’962 Mt of CO2 have been emitted worldwide46.
Table 10: CO2 abatement potential (in million tons, Mt; rounded)
in Mt CO2
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
2020
90
220
800
2030
160
560
1‘500
2050
310
2‘000
3‘500
3.1.5 Resulting current and future aluminium use in solar collectors
Table 11 shows the cumulative mass of aluminium which is used in solar thermal collectors.
By 2050, the total global use of aluminium in solar thermal collectors will vary between approximately 0.14 Mt in the SCENARIO LOW, 16.5 Mt in the SCENARIO BEST ESTIMATE
and approximately 69.2 Mt in the SCENARIO HIGH. In the latter, the replacement potential
of aluminium is fully tapped and technology development takes place according to the PATH
HIGH.
Figures shown in Table 12 indicate the annual total aluminium use per decade. Further, aluminium use as percentage of annual global aluminium production is calculated.
For example, in SCENARIO BEST ESTIMATE, the annual average aluminium use in the
decades 2031-2050 is expected to be around 0.6 Mt for evacuated tube and flat-plate collectors; equalling 1.6% of annual aluminium production. SCENARIO BEST ESTIMATE Plus
shows, that with moderate assumptions on installation rates but with a maximized use of
aluminium, even 4.4% could be realized.
45
46
Federal Ministry of Environment, Germany (2009a): p. 24.
IEA (2009): p. 45.
30
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Table 11: Total cumulative use of aluminium for solar collectors (in million tons)
in Mt
2020
2030
Flat-plate collectors
SCENARIO LOW
0.02
0.03
SCENARIO BEST ESTIMATE Minus
0.04
0.1
2050
0.06
0.37
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
1.26
1.73
3.26
4.48
11.47
15.75
SCENARIO HIGH
6 .1
12.2
27.7
Evacuated tube collectors
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
0.026
0.06
0.046
0.16
0.086
0.56
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
0.55
2.59
1.42
6.71
5
23.59
SCENARIO HIGH
9.11
18.21
41.53
Total aluminium use
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
0.043
0.1
0.076
0.26
0.143
0.93
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
1.81
4.32
4.68
11.19
16.47
39.34
SCENARIO HIGH
15.21
30.41
69.23
Table 12: Future annual aluminium use (average of decade) in tons and percentage of global annual
aluminium production
Annual Al use in
Annual Al use as percentage of
annual global Al production 1
tons
SCENARIO LOW
2010-2020
2‘500
0.01 %
2021-2030
3‘300
0.01 %
2031-2050
3‘350
0.01 %
SCENARIO BEST ESTIMATE Minus
2010-2020
2021-2030
2031-2050
8‘200
17‘800
75‘200
0.02 %
0.05 %
0.21 %
SCENARIO BEST ESTIMATE
2010-2020
2021-2030
2031-2050
SCENARIO BEST ESTIMATE Plus
2010-2020
2021-2030
2031-2050
150‘000
287‘000
589‘500
0.41 %
0.79 %
1.62 %
357‘000
762‘000
1‘586‘000
1.0 %
2.1 %
4.4 %
SCENARIO HIGH
2010-2020
2021-2030
2031-2050
1‘446‘000
1‘520‘000
1‘941‘000
3.97 %
4.18 %
5.33 %
1
Aluminium production in 2009 was approximately 36.4 million tons (IAI Statistics 2010).
31
Aluminium and Renewable Energy Systems
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3.2 Wind turbines
Energy from wind is an indirect form of solar energy, and thus can be counted as a renewable energy resource. Wind energy exists as kinetic energy of moved atmospheric air
masses and can be converted into a useful form of energy, namely electricity. Wind turbines
can be deployed in all climatic areas, on land (onshore) along the coastline, inland or in
mountainous territories as well as at sea (offshore).
3.2.1 Description of technologies
The most common way to convert wind energy into wind power is to generate electricity with
(small and large) wind turbines. Three different technologies exist: large wind turbines (onshore and offshore) and small wind turbines. Onshore turbines are wind turbines which are
located on solid ground. Offshore wind turbines are installed on marine shelves off the coast
(see Figure 20).
Figure 20: top left: wind farm Morbach (Germany) with Vestas V80 (2 MW); top right: small wind turbine WES WESpe (5 kW); bottom: offshore wind farm Rodsand I (Denmark), operator: E.ON Sverige47
During the last 20 years, technical development of wind turbines has mostly concentrated on
constructing progressively larger systems in order to optimally exploit locations with good
wind conditions. This goal has spurred on quick technical development. While the average
capacity of installed wind turbines was less than 50 kW in 1987, it increased by nearly a factor of forty to 1.9 MW by mid-2008. The largest systems today have a maximum capacity of 6
MW. The yield of such a plant corresponds to the yearly electricity consumption of up to
5’000 households. As the capacity of turbines increased hub heights and rotor diameters did
also.
Many systems use intermediary gears which transform the low rotor speed to the required
generator speed of 1’500 revolutions per minute. However, losses of about 2% per stage are
attributed to the gears. Additionally the gears are themselves a source of noise emissions.
47
Sources: Vestas, Wes-Energy, E.ON.
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Gearless systems do not face these problems; however they require specially manufactured
and very large multi-pole generators48.
Small wind turbines offer additional potential for using wind energy. So far there is no single
definition of small wind turbines. The German law on feed-in from renewable energies (EEG)
defines the upper limit for small wind turbines at 30 kW of installed capacity. According to
DIN regulation49 the limit for small wind turbines is at a rotor area of 200 m2 (plus additional
voltage limit). The Federal Wind Energy Association (BWE) refers to two limitations: 200 m2
and 100 kW of installed power. In addition, some building codes and regulations refer to different altitude limits which vary from 10 m to 65 m.
Small wind turbines can be distinguished in horizontal and vertical small wind turbines. The
terms horizontal and vertical refer to the arrangement of the axis of rotation. Applications for
small wind turbines are mainly in developing and emerging countries, in rural areas to supply
the network infrastructure or in decentralized solutions to cover the energy demand.
3.2.2 Current market situation for large wind turbine systems
Installed capacity worldwide
As of the end of 2009 the current global installed capacity of wind turbines is 159.9 gigawatts
(GW), nearly half of them being located in Europe (76 GW)50. Another 39 GW are installed in
Asia which is almost exactly the capacity of the wind power in North America (38 GW). In the
Pacific Region there are actually 2 GW. Another 2 GW are installed in Africa, in the Middle
East, in Latin America and in the Caribbean. Figure 21 indicates regional shares of the current global existing capacities in percent. Markets in Europe, Asia and North America contribute most to the current capacity installed.
Africa &
Middle East
1%
Europe
48%
Asia
25%
North
America
24%
Pacific
Region
1%
Latin America
& Caribbean
1%
Figure 21: Installed capacity by regions
Since it is important to know where key markets can be found, regional shares of capacities
must be broken down to the country level. In Table 13 country shares of the capacity in GW
and percentage shares are shown for Top 10 countries.
48
Federal Ministry of Environment, Germany (2009c): p. 64.
DIN EN 61400-2:2007.
50
Global Wind Energy Council (2010): Statistics. / Bundesverband Windenergie e.V. (2010): Statistics.
49
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Table 13: Share of wind turbine capacity, Top 10 countries, 200951
Country
Installed capacity 2009 in GW
Share of capacity 2009 in percent
USA
35.2
22.3 %
Germany
25.8
16.3 %
China
25.1
15.9 %
Spain
19.1
12.1 %
India
10.9
6.9 %
Italy
4.9
3.1 %
France
4.5
2.8 %
UK
4.1
2.6 %
Portugal
3.5
2.2 %
Denmark
3.5
2.2 %
Others
21.4
13.6 %
World total
158
100 %
The US is the undisputed world leader with 35 GW capacity installed, followed by Germany
(26 GW), China (25 GW) and Spain (19 GW). These countries account for almost two thirds
(or 66%) of the capacity in 2009 (see Figure 22). Other countries follow but lag behind in
terms of quantity of the capacities compared to the top four countries.
Rest of
Europe
13%
Spain
12%
India
7%
Others
14%
China
16%
USA
22%
Germany
16%
Figure 22: Share of wind turbine installed capacity 2009 (Source: Global Wind Energy Council (2010):
Statistics)
In order to identify growing key markets it is worth taking a look at data that provides information on development meaning newly installed capacities (see Table 14). The countries which
had the highest newly installed capacity in 2009 were China (13 GW), the USA (9.9 GW),
Spain (2.5 GW), Germany (1.9 GW) and India with 1.3 GW.
According to the data mentioned, one of the future key markets will be China, which is rich in
wind resources. Additionally China has chosen wind power as an important alternative
51
Source: Global Wind Energy Council (2010): Statistics.
34
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source in order to rebalance the energy mix, combat global warming and ensure energy security. Supportive measures have been introduced52.
Concerning the US, increasingly high growth rates for wind turbines will persist because of
the existence of the production tax credit and the favourable energy policy environment.
Especially the rapid market development since 2000 has contributed to this increased expansion. The capacity increased in the last eleven years from 10 GW in 1998 to 160 GW
2009. 38 GW of this performance was newly installed in 200953.
Table 14: Wind turbines: Added capacity in 2009
Country
Added capacity in 2009
Growth rate 2009 in %
China
13.0 GW
34.7 %
USA
9.9 GW
26.5 %
Spain
2.5 GW
6.6 %
Germany
1.9 GW
5.1 %
India
1.3 GW
3.4 %
Rest of the world
9.5 GW
23.7 %
World Total
37.5 GW
100.0 %
The share of offshore wind farms which are installed on high seas in Europe are expected to
be about 4 percent in 201054. The vast majority of these facilities were situated in the North
Sea and the Baltic Sea. Twenty new projects in the aforementioned regions are being
planned. In the future, however, offshore wind power is expected to gain greater importance.
Key manufacturers and market actors
Currently, the largest market share, of manufacturers of wind turbines, is held by the Danish
company Vestas with 19.8 percent55 (see Figure 23). Other large manufacturers are GE
Wind from the USA (17 percent), Gamesa from Spain (12 percent), Enercon from Germany
(ten percent) and the Indian company Suzlon which has a market share of nine percent. A
quarter of the entire wind turbine manufacturer market is constituted by five companies,
namely Siemens (Denmark), Sinovel and Gold Wind (both from China), Acciona (Spain) and
Nordex (Germany). Each of them has a market share between three and seven percent.
Nearly 18 percent fall back on smaller manufacturers with market shares below 3.5 percent.
52
Global Wind Energy Council (2008).
Global Wind Energy Council (2010): Statistics. / Bundesverband Windenergie e.V. (2010): Statistics.
54
EWEA (2010): p.9. (Note: Figures on global offshore status not found during research.)
55
BTM Consult Aps (2009).
53
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Sinovel
(China)
5%
Gamesa
(Spain)
11%
GE Wind
(USA)
18%
Siemens
(Germany)
7%
Enercon
(Germany)
10% Acciona
(Spain)
4%
others
17%
Suzlon
(India)
9%
Vestas
(Denmark)
19%
Figure 23: Key market actors (Source: BTM Consult Aps (2009): World market update 2009)
The market for small wind turbines is only a niche market which is actually not developed in
such a way that detailed market information is available. According to the American Wind
Energy Association 19’000 units of small wind energy turbines were sold in 2008; of which
the overwhelming majority were sold in the sector of below 10 kW56.
Table 15 below lists key manufacturers of small wind turbines in the German and international manufacturers of vertical and horizontal wind turbines. Market information on market
shares of these different manufacturers is not available.
Table 15: Selected manufacturers of small wind turbines57
Manufacturer
Country
Ampair
England
Inno Energy
Germany
Nakao Intl
USA
Partzsch
Germany
Ropatec
Italia
Sinuswind
Germany
TASSA
Germany
VENCO
Netherlands
WES Energy
Germany
winDual
Germany
3.2.3 Specific aluminium use in wind turbine systems
Life cycle assessments (LCA) of ten onshore wind turbines with power ranging from 30 kW to
3 MW and the LCAs of five offshore wind turbines with power ranging from 2 MW to 4.5 MW
have been analyzed (see Table 17). To get a significant result LCAs of wind turbines of
56
57
AWEA 2009.
Federal Ministry of Environment, Germany (2009b).
36
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manufacturers which are key market players in the wind energy sector have been examined.
Data derived from LCA’s provided by Nordex, Vestas and Enercon is supplemented by the
wind turbines data from smaller manufacturers and reference turbines from the different
LCA’s of reliable and relevant studies.
LCA’s which have been analysed for this report:
-
BAUER, B. / BAUER, C. (2007): ECOINVENT - TEIL XIII: WINDKRAFT. VILLINGEN,
SWITZERLAND.
-
ELSAM ENGENEERING (2004): Life Cycle Assessment of offshore and onshore sited
wind farms. Fredericia, Denmark.
-
DONG ENERGY (ed.) (2008): NEEDS - Final report on offshore wind technology. Hamburg, Germany.
-
EUROPEAN COMMISSION (ed.) (2009): Environmental and ecological life cycle inventories for present and future power systems in Europe (ECLIPSE): Life Cycle Inventories. Brussels, Belgium.
-
VESTAS (2006a): Life cycle assessment of electricity produced from onshore sited
wind power plants based on Vestas V82-1.65 MW turbines. Randers, Denmark.
-
VESTAS (2006b): Life cycle assessment of offshore and onshore wind power plants
based on Vestas V90-3 MW turbines. Randers, Denmark.
Large wind turbines
To make a precise statement, wind turbines were subdivided into their component parts. A
common wind turbine consists of a foundation (or basement), a tower, a nacelle and a rotor
(see Figure 24). Preconditions for a grid connection are (internal and external) cables and a
cable station. Because offshore wind farms need additional transformers, transmission infrastructure and cable stations that switch electricity to the adequate grid the specific aluminium
use is higher compared to onshore systems.
The foundation that is embedded underground is mostly made of concrete and steel. The
main material used for the tower is steel. The nacelle, which consists of a motor that moves
the rotor, consists mainly of copper, iron and steel. The rotor, which actually consists of the
hub and blades, usually has three blades that consist of fibreglass.
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Figure 24: Structure of a wind turbine (Source: Government of New South Wales, Australia)
The material which is predominately used in wind turbines is steel (partly high strength steel)
with about 85% of the total material input. Cast iron and fibreglass (especially for the blades)
are about 5% of the total material input. Aluminium only plays a subordinate role. There is no
significant trend in which aluminium parts can be used in a significantly higher amount. “Material usage is and will continue to be dominated by steel, but opportunities exist for introducing aluminium or other light weight composites, provided strength and fatigue requirements
can be met”58.
The covering of the wind turbine nacelle is mostly made of plastic or steel, but could also be
made of aluminium which is already the case in the Enercon wind turbines. The nacelle itself
is actually produced with cast iron but could also be made of aluminium. Enercon is the
trend-setter using aluminium for nacelles. The nacelle casing of Enercon's E-82 wind turbine,
winner of European Aluminium award 2008, is no longer made of glass-fibre reinforced plastic (GRP) but aluminium. Enercon expects that other European wind turbine manufactures
will also replace the GRP nacelles stepwise. Aluminium is used in the E-82 for four reasons:
1) maximum material recyclability, b) minimum fire risk, c) lightning protection is improved as
the nacelle has the function of a Faraday cage and d) the nacelle surface helps cool the nacelle components, therefore extending their operational life span.
During the past 20 years, large wind turbine blades have been fabricated from steel, aluminium, and composite materials such as wood, fibreglass, and carbon fibers. For a given blade
strength and stiffness, the blade should be as light as possible to minimize inertial and gyroscopic loads, which contribute to blade fatigue. Blades made from steel and aluminium suffers from excessive weight and low fatigue life relative to modern composites. Because of
these limitations, during the past 10 years almost all blades have been fabricated from composite materials, usually fibreglass. Vestas also used aluminium in older models (Vestas V82) but stopped the use of aluminium in the newer technology (Vestas V-90) in this component59. The tower consists mainly of steel which is the basic material for the frame and the
exterior shell. Only subordinate parts of the tower like the ladder and the lift can be made
from aluminium.60
58
US Department of Energy (2001).
National Renewable Energy Laboratory (2001): p.5.
60
Interview with Mr Höhl, Nordex area manager South Germany.
59
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Results at a glance:

the aluminium use in wind turbines of different manufacturers varies significantly in
the different components;

aluminium is used in tower (especially ladder and lift), rotor (frame) and nacelle (base
support and nacelle cover);

only one LCA attests aluminium in the foundation;

an additional transmission (cable station and transformer) is needed for offshore electricity generation;

internal and external cables are treated in an ‘excursion’ (at the end of the chapter).
Small wind turbines
The market for small wind turbines is very small. As mentioned above the total sale of small
wind turbines was 19’000 units in 2009. However, the market is increasing at the moment
and there will be more potential in the future. But with regard to the components of small
wind turbines aluminium use is very low. Only some components share a negligible amount
of aluminium. The only components which have potential are rotor blades.
Thus, small wind turbines will not be focussed on due to two reasons: 1) Aluminium use in
small wind turbines is negligible and therefore aluminium’s potential is expected to be low in
the future. 2) No scientific assumption on the market development of small wind turbines in
the future can be made. Thus, small wind systems are not included in the calculations.
Resulting specific aluminium use
For calculation of actual and future aluminium use in wind energy systems, three specific
aluminium demands were calculated for on- and offshore systems. Results are indicated in
Table 16.
Onshore wind turbines
The minimum aluminium use of the analyzed LCA’s was in the Enercon E-112 wind turbine.
With its hub height of 124 meters and a capacity of 4.5 GW the turbine represents little aluminium usage. For onshore electricity generation there is a specific aluminium use of 0.05
kg/kW (Al minimum). Moderate aluminium with 0.26 kg/kW (Al moderate) is to be found in
Vestas V-90 wind turbines. The turbine has a capacity of 3 GW and a hub height of 80 meters for offshore use and a height of 105 meters for onshore use. The maximum specific
aluminium use is given in the reference turbines of the ECLIPSE LCA’s. There it was supposed that the whole nacelle casing is made of aluminium so that a high amount of aluminium is needed. Al maximum is 3.53 kg/kW.
Offshore wind turbines
To generate electricity with offshore wind an additional transformer and a cable station to
transport the electricity through marine cables to the mainland are needed. On land the electricity then gets transmitted in an amount equal to the transmission from onshore wind turbines. Because of the additional need of a transformator and a cable station, which are both
39
Aluminium and Renewable Energy Systems
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partly made of aluminium, an additional specific aluminium factor for offshore wind energy is
needed.
Al minimum with 0.26 kg/kW is processed in the Enercon E-112 plus additional components
(which is evenly used for on- and offshore application). The moderate specific aluminium use
per kWh is 1.06 kg for Vestas V-90 offshore turbine plus additional components (Al moderate). The reference turbine from ECLIPSE showed maximum aluminium use with 3.93
kg/kW (Al maximum).
Table 16: Specific aluminium use in wind turbines [in kg/kW]
in kg/kW
Al minimum
Al moderate
Al maximum
Onshore
0.05
0.26
3.53
Offshore
0.26
1.06
3.93
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Table 17: Life cycle assessments (LCA) of wind turbines examined
Offshore
ref. turbine Enercon
[unit]
Eclipse
E-112
Power
2.5 MW
4.5 MW
80
124
Onshore
Needs
2 MW
ECOinvent Vestas V90
2 MW
3 MW
60
80
Nordex
Nordex Enercon ref. turbi- Enercon Vestas Vestas
Vestas
N43/600
N50/800
E-66
ne Eclipse
E-112
V82
V90
600
1.65
600 kW
800 kW 1.5 MW
2.5 MW
4.5 MW
3 MW
kW
MW
40
35
50
67
80
124
78
105
2‘600
99
99
500
204
1‘850
207
127
8‘820
127
Hub height
Tower
Rotor
Nacelle
Basement
m
kg
kg
kg
kg
Aluminium
use turbine:
kg
8‘820
226
1‘595
845
1‘950
204
1‘850
207
226
8‘820
226
3‘100
781
Specific aluminium use
kg/kW
3.53
0.05
0.80
0.42
0.65
0.34
3.08
0.26
0.15
3.53
0.05
1.88
0.26
Al MAX.
Al MIN.
Transformator
kg
Cable station
kg
Transmission
kg
per wind farm
Transmission
kg
per turbine
Total
kg
Specific aluminium use
kg/kW
transmission
offshore
Total specific
aluminium
kg/kW
use
8‘820
99
127
2
43.3
845
1‘550
1‘220
418.1
1‘220
2013.5
3‘170
0.4
0.21
0.21
0.4
3.93
0.26
1.01
1.06
Al max.
Al min.
Al mod.
41
Al
MED.
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3.2.4 Technology scenarios for wind turbines
Depending on the year of the studies the projected wind capacity for 2010 in some scenarios
has already been surpassed by the actual installed capacity in 2009. This applies particularly
to the baseline scenarios which project developments under the current state of the art/ business-as-usual path as they fade out market incentives and technological innovations. The
lowest projected wind energy capacity for 2020 is given by Greenpeace (2008), low scenario
and projects 346 GW (see Figure 25).
The scenarios that can be classified as moderate are the GWEC (2008) moderate scenario
and Peter/Lehmann (2007), high. All precede an installed wind capacity of around 700 GW.
Even the scenario of Peter/Lehmann (2007), low is only slightly below the range (550 GW).
in GW
EWEA (2009)
3'500
Peter/Lehmann (2007), high
3'000
Peter/Lehmann (2007), low
2'500
MEF (2008), low
2'000
MEF (2008), high
1'500
Greenpeace (2008), low
1'000
Greenpeace (2008), high
GWEC (2008), low
'500
GWEC (2008), moderate
'0
today
2020
2030
2040
2050
GWEC (2008), high
Figure 25: Installed capacity of wind turbines (onshore and offshore) in different technology scenarios
For 2030, the projections of the expansion scenarios clearly diverge, depending on the philosophy and assumptions of the scenarios. The two reference scenarios of Greenpeace
(2008), low (440 GW) and the GWEC (2008), low are below or around 500 GW. A set of
scenarios an installed capacity for wind power between 1’000 and 1’600 GW. The GWEC
(2008), high scenario and Peter/Lehmann (2007), high represent the highest expansion
stages of wind with about 2’500 GW.
In our definition of the scenarios, we set PATH LOW corresponding to the Greenpeace
(2008) low scenario (see Table 18 and Figure 26). PATH BEST ESTIMATE corresponds to
Peter/Lehmann (2007), low for 202061, and to MEF (2008), low for reference years 2030 and
2050. PATH HIGH corresponds to GWEC (2008), high scenario for 2020 and 2030, then to
MEF (2008), high. The installed wind capacity today is 158 GW, according to most recent
figures62.
61
Projections of Peter/Lehmann are very reasonable as they are based on actual global wind conditions (wind speed and suitable sites for wind turbines), but are only projected until 2020.
62
Global Wind Energy Council (2010).
42
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Table 18: Wind turbine scenarios: PATH LOW, PATH BEST ESTIMATE, PATH HIGH
in GW
today
2020
2030
2050
PATH LOW
158
346
440
526
PATH BEST ESTIMATE
158
550
1‘000
2‘000
PATH HIGH
158
1‘080
2‘375
3‘500
in GW
3'500
3'000
PATH HIGH
2'500
2'000
PATH BEST
ESTIMATE
1'500
1'000
PATH LOW
'500
'0
today
2020
2030
2040
2050
Figure 26: Development of wind installed capacity in the scenarios PATH LOW, PATH BEST
ESTIMATE, PATH HIGH
For market shares of onshore and offshore, it is assumed that offshore wind turbines increase more dynamically than onshore wind (see Figure 27). Today, onshore turbines contribute to 97%63. But the technology costs have decreased strongly as well as technical development and investments in offshore technology increased so that offshore electricity generation will become more and more important in the future. By 2020, offshore wind energy
will contribute significantly more. It is estimated that around 15% of wind energy generation
will come from offshore. After 2020, “offshore wind development even speeds up, so that – in
the end – the onshore/offshore ratio is about two-thirds onshore and one third-offshore
wind”64. The share of offshore energy could even rise to 40% by 205065.
63
Peter/Lehmann (2007): p.37.
64
ibd.
65
IFEU estimate.
43
Aluminium and Renewable Energy Systems
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today
2020
85%
97%
3%
15%
2050
2030
67%
60%
40%
33%
Figure 27: Market share onshore (green) and offshore (orange) wind turbines
Based on the defined capacity development electricity generation and CO2 mitigation of wind
systems were calculated. Toward this end different studies were evaluated to derive full-load
hours66. We assume full-load hours according to Table 19 which will increase in the next 40
years because of higher hub heights and better developed technologies.
Table 19: Expected full load hours today and in future (worldwide average, rounded)
in h/a
2020
2030
2050
Onshore
2’150
2’300
2’400
Offshore
3’600
3’800
4’200
For generation of electricity from wind energy there will be a range of 820 TWh (SCENARIO
LOW) and 2’550 TWh (SCENARIO HIGH) for 2020 and a range of 1’640 TWh and 10’920
TWh for the reference year 2050. By comparison the global electricity generation in 2007
was 19’771 TWh67.
Table 20: Energy production (in TWh, rounded)
in TWh
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
66
67
2020
820
1‘310
2‘550
2030
1‘230
2‘790
6‘640
2050
1‘640
6‘240
10‘920
Sachverständigenrat Umwelt (2010): p. 51. European Wind Association, EWEA (2009): p. 66.
IEA (2009): p. 26.
44
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For CO2 abatement the factor is actually higher than in the electricity mix because wind energy replaces conventionally produced energy from marginal power plants.
The determination of a global substitution factor for wind energy is not possible within this
study because it requires detailed energy economic modelling. In the literature there is no
globally calculated substitution factor available. We calculate with a substitution factor of 780
g/kWh68, a factor that was derived for Germany based on an analysis of marginal power
plants substituted by wind. As a first-order estimate it seems reasonable to use this factor as
it constitutes a combination of hard coal based electricity production as well as gas (combined cycle and gas turbine electricity production). These three power plant types are, in
many countries worldwide, the medium load technologies which can be technically reduced
in power with adequate flexibility and are in a position of the marginal cost merit order crossing the demand curve (for a detailed explanation of the merit order, see IFEU (2008): Steinkohle-Kraftwerk Hamburg-Moorburg und seine Alternativen).
The resulting CO2 abatement of wind turbines is about 230 Mt of CO2. In 2020, the abatement potential for SCENARIO HIGH increases to about 2’000 Mt CO2. For 2030 and 2050, in
SCENARIO HIGH CO2 abatement will be 5’200 Mt and 8’500 Mt respectively (see Table 21).
Table 21: CO2 abatement potential (in million tons, Mt; rounded)
in Mt CO2
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
2020
600
1’000
2’000
2030
1‘000
2’200
5’200
2050
1’300
4’900
8’500
3.2.5 Resulting current and future aluminium use in wind turbine systems
The SCENARIO BEST ESTIMATE projects a total aluminium use in wind energy systems of
0.2 Mt in 2020, 0.5 Mt in 2030, and 1.2 Mt in 2050 (Table 22). SCENARIO HIGH shows a total aluminium use of 12.9 Mt in 2050. Total maximum aluminium use in 2020 and 2030 could
be 3.9 Mt and 8.7 Mt, respectively. In 2020 the SCENARIO LOW indicates only negligible
amounts of aluminium used.
Table 22: Total use of aluminium in on- and offshore wind (in million tons)
in million tons
Onshore
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
2020
2030
2050
0.015
0.023
0.122
1.650
0.015
0.034
0.174
2.365
0.016
0.06
0.312
4.236
SCENARIO HIGH
3.241
5.617
7.413
Offshore
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
0.014
0.021
0.088
0.324
0.038
0.086
0.350
1.297
0.055
0.208
0.848
3.144
68
Klobasa et al. (2009): p. 23.
45
Aluminium and Renewable Energy Systems
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SCENARIO HIGH
0.637
3.080
5.502
Total aluminium use
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
0.03
0.04
0.20
1.97
0.05
0.12
0.52
3.66
0.07
0.27
1.16
7.38
SCENARIO HIGH
3.88
8.70
12.92
To get an approximation on the amount of aluminium use the annual aluminium use is calculated (see Table 23).
Table 23: Future annual aluminium use (average of decade) in wind energy system and percentage of
global annual aluminium production
Annual Al use
in decade in tons
Annual Al use as percentage of annual Al production1
SCENARIO LOW
2010-2020
2021-2030
2031-2050
1‘980
2‘400
2‘350
0.005 %
0.007 %
0.006 %
SCENARIO BEST ESTIMATE Minus
2010-2020
2021-2030
2031-2050
3‘600
8‘300
9‘200
0.01 %
0.02 %
0.03 %
16‘500
31‘400
31‘800
0.05 %
0.09 %
0.09 %
141‘486
224‘714
256‘6432
0.4 %
0.6 %
0.7 %
331‘800
481‘900
404‘800
0.09 %
0.13 %
SCENARIO BEST ESTIMATE
2010-2020
2021-2030
2031-2050
SCENARIO BEST ESTIMATE Plus
2010-2020
2021-2030
2031-2050
SCENARIO HIGH
2010-2020
2021-2030
2031-2050
1
0.11 %
Aluminium production in 2009 was approximately 36.4 million tons (IAI Statistics 2010).
As can be seen from these figures from all scenarios, the highest market potential of aluminium is given in decades 2010-2020 and 2021-2030. Afterwards, due to market saturation and
lack of optimal locations with wind potentials, aluminium use will resume at the same level or
even decrease.
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For example, in the SCENARIO BEST ESTIMATE aluminium use is highest from 2021-2030
with around 31’400 tons per year. In this decade, annual aluminium use accounts for approximately 0.09 % of annual aluminium production. Compared to the solar collector estimate
this figure is relatively low. With equal installation rates but maximized aluminium use (Al
moderate  Al Maximum) in SCENARIO BEST ESTIMATE Plus, 0.7% of annual aluminium
production could be achieved.
3.2.6 Cables and wind turbines (excursion)
Cables are needed to transport the electricity from the turbines to the electricity grid. In future
the importance of offshore wind electricity generation will rise to a share of nearly one third of
the total wind capacity in the year 2030. Therefore the distances between the place where
the electricity is generated (at sea) and the place where the energy is needed will also rise.
With regard to aluminium use it is very interesting to closely follow this development. The use
of aluminium for external cables is high and is about one third of the total material use of the
cables. Therefore the increasing use of cables (especially marine cables) offers a good potential for the aluminium industry. The internal cables can also be produced with aluminium.
The producers we spoke to mainly use standard NYM cables with 400 volts. These sorts of
cables consist primarily of copper with a plastic casing.
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3.3 Photovoltaic sytems
3.3.1 Description of technologies
Photovoltaic systems (PV) directly convert solar energy into electricity. The basic building
block of a PV system is the PV cell, which is a semiconductor device that converts solar energy into direct-current (DC) electricity. PV cells are interconnected to form a PV module.
The PV modules combined with a set of additional application-dependent system components (especially inverters and mounting systems), form a PV system. PV systems are highly
modular, i.e. modules can be linked together to provide power ranging from a few watts to
tens of MW.
The most common technologies used in photovoltaic cells are based on crystalline silicon
and thin film methods. Crystalline silicon has dominated photovoltaic production from the beginning. It is widely available, has proven reliability and is scientifically well understood due to
it being founded on the knowledge and technology originally developed for the microelectronics industry. Crystalline silicon module production starts with the melting of purified silicon
then different techniques are applied to produce ingots or ribbons with variable degrees of
crystal perfection. Afterwards ingots are shaped into bricks and sliced into thin wafers by
wire-sawing. In the case of ribbons wafers are cut from the sheet using a laser. Cut wafers
and ribbons are processed into solar cells and interconnected in weather-proof packages.
The two main types of crystalline silicon are: single crystalline silicon (sc-Si) and multicrystalline (mc-Si). Sc-Si is characterized by atomic layers all oriented in the same direction
in a single silicon crystal. High purity crystal implies higher cell efficiencies (maximum efficiency: approx. 23%). Multi-crystalline silicon is made from small-area clusters of singlecrystalline. The clusters are all oriented in different directions, giving the aesthetic effect of
non-homogeneous reflection of the wafer. In fact the borders of cluster areas are a semiconductor “defect”, leading to poorer electron transmission and therefore lower cell efficiency
(maximum efficiency: approx. 15%). Recently ribbon technology has been developed where
wafers, in the form of ribbons, are pulled directly from the silicon without the production of the
ingot and the need to cut it in wafers.
Thin films are based on a completely different manufacturing approach: instead of producing
an ingot and then cutting it into wafers, thin films are obtained by depositing extremely thin
layers of photosensitive materials on a low cost backing such as glass, stainless steel or
plastic. The first thin film produced historically was amorphous silicon (a-Si) (efficiency
approx. 7%). More recently, other thin film technologies have been developed, i.e. Cadmium
Telluride (CdTe, maximum efficiency: 11%) and Copper-Indium-Diselenide (CIS, maximum
efficiency: 12%).
Emerging PV technologies are comprised of advanced inorganic thin film technologies (e.g.
Si, CIS) as well as organic solar cells.
3.3.2 Current market situation for photovoltaic systems
The global PV market has experienced dynamic growth for more than a decade with an average annual growth rate of up to 40%. The installed PV power capacity has grown from 0.1
GW in 1992 to 14 GW in 2008 whereby in 2008 alone 6 GW were installed69.
69
IEA (2010): p. 9.
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Four countries have an installed PV capacity of one GW or more: Germany (5.3 GW), Spain
(3.4 GW), Japan (2.1 GW) and the US (1.2 GW). These countries account for almost 80% of
the total global capacity. Other countries (including Australia, China, France, Greece, India,
Italy, Korea and Portugal) are gaining momentum due to new policy and economic support
schemes (see Figure 28 and Table 24).
Economies like China and India have become global solar forces in the past decade and will
remain important key players in the future. The potential of PV for widespread electricity
generation is substantial in Latin America and Africa. These world regions may become very
important markets in the mid- to long-term. In Brazil, a leading country in the use of PV for rural electrification70, the market is currently dominated by multinationals with no national
manufacturers. However, with the support of the government, the Brazilian Centre for Development of Solar PV Energy (CB-Solar), created in 2004, has developed a pilot plant to
manufacture cost effective PV modules and silicon solar cells at scale71.
China
1%
Germany
36%
Spain
23%
Others
15%
South
Korea
2%
Japan
15%
USA
8%
Figure 28: Market share of installed capacity
Table 24: Solar PV: Existing and added capacity, 2007
Additions 2008 in GW
Existing 2008 in GW
Growth rate 2008 in %
Germany
1.5
5.4
27 %
Spain
2.6
3.3
78%
Japan
0.24
1.97
12 %
USA
0.25
0.73
34 %
Other EU
0.4
0.75
53 %
South Korea
0.25
0.35
71 %
Others
0.2
0.45
44 %
As for a technology distribution crystalline modules (sc-Si and mc-Si) represent approximately 87 % of the global annual market today (see Figure 29). Thin films currently account
for approximately 12 % of global PV module sales (amorphous (a-Si) and micromorph silicon
70
71
IEA (2010): p. 15.
IEA (2010): p. 16.
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(a-Si/μc-Si), ii) Cadmium-Telluride (CdTe), and iii) Copper-Indium-Diselenide (CIS). Emerging technologies are about to enter the market via niche applications (1%)72. In the future,
thin film technology application will increase as prices for silicium rise.
Crystalline
technologies
87%
Thin film
technologies
12%
Emerging
technologies
1%
Figure 29: Market shares of PV technologies
Table 25: Key manufacturers of PV systems73
Company
Suntech
Sharp
Q-Cells
JA Solar Holdings
Mitsubishi Heavy
Kyocera
Trina Solar
SunPower
Gintech
Motech
Ningbo Solar Electric
Sanyo
E-Ton Solar
Schott Solar
Neo Solar
Bosch
Canadian Solar
SolarWorld
China Sunergy
First Solar
72
73
Country
China
Japan
Germany
China
Japan
Japan
China
Philippines
Taiwan
Taiwan
China
Japan
Taiwan
Germany
Taiwan
Germany
China
Germany
China
USA
Production in MW
704
595
551
520
421
400
399
397
368
296
260
260
220
218
201
200
200
200
194
143
IEA (2010): p. 7.
Compiled from Hirshman (2010): pp. 176-199; Hirshman (2009): pp. 170-206.
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3.3.3 Specific use of aluminium in photovoltaic systems
Aluminium is found in three main components of a solar PV system: inverter, panel and
mounting structure. A PV inverter is an electrical inverter that is made to change the direct
current (DC) electricity into alternating current (AC). Here the casing is made of aluminium.
Figure 30: PV inverter with aluminium casing (top), slanted roof mounting structure (bottom left), panel
frame made of aluminium74
For the panel aluminium can be used to achieve enhanced cell performance via a back surface field formation. Therefore a so called metallization paste, which can contain aluminium
e.g., is attached to the backside of the panel to reduce stress and the bowing of thin film75.
Most of the aluminium is used in the frame of the panel. The advantage of aluminium is that it
is lighter than other metals which are very important for construction/mounting. 78% of PV
analyzed, from 772 modules made by 166 producers, used aluminium for the panel frame,
15% were frameless panels, and only one percent used other materials (e.g. glass, synthetics)76 (see Figure 31).
74
Sources: Comel, Cool Power, Jiangyin Lutong Industrial Co., Ltd.
Carroll et al. (without year): p. 1.
76
Own analysis; Source: Photon, February 2010: pp. 14-47.
75
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Aluminium
78%
n/a
6%
Frameless
15%
Others
1%
Figure 31: PV panel frame materials used
It is necessary to have a faultless roof for panels to be mounted on slanted roofs. The mounting system uses wood, aluminium or steel that is directly attaches to the roof. Panels can
also be integrated into a slanted roof. First the roof tiles are removed in the area foreseen for
the solar laminates and then steel profiles are screwed into the tile slats. Different aluminium
profiles can be used to make a frame for the laminate. Rubber is attached to these profiles
and the laminates are placed within these frames and connected to the electric system. All
edges are sealed with rubber or silicone. Steel sheets are mounted in gap between roof tiles
and solar laminates77.
Flat roof mounted PV systems use gravel for the foundation. Insulating mats, aluminium profiles and smaller components are the main parts of the mounting system. First any sand or
gravel is cleaned from the roof. A mat made from recycled plastic is attached for the protection of the roof and then foundation is made with loose gravel and placed on the plastic
sheet. Aluminium profiles are mounted and the panels fixed to this foundation.
When panels are mounted to a façade they are placed together on an aluminium profile
which is attached to the façade. If available the modules are attached to the construction
steel in the wall78.
In order to determine the current use of aluminium in grid-connected photovoltaic systems
different small scale plants of 3 kWp capacity have been examined79. The plants differ according to the cell type (single and multicrystalline silicon, ribbon-silicon, thin film cells with
CdTe and CIS), and the place of installation (slanted roof, flat roof and façade) (see above
for explanation of different cell types). Slanted roof and façade systems are further distinguished according to the kind of installation (building integrated i.e. frameless laminate or
mounted i.e. framed panel). Figures for the above mentioned systems were analyzed by examining different LCA studies, especially the detailed Ecoinvent LCA on photovoltaics.
As for ground mounted systems, which were not part of the Ecoinvent LCA, the literature
does not supply data. According to the German monitoring report on ground mounted PV
fields, mounting constructions are mainly made of metal; only 10 % of surveyed 159 PV
77
Jungbluth (2009): p. 90.
Jungbluth (2009): p. 90.
79
Jungbluth. (2009): p. 90.
78
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fields are made of wood80. Ground mounting facilities primarily use a rammed post construction technique with profiles to hold PV panels on top of posts.81 (see Figure 32). Ramming
post are not made from aluminium but from steel because steel does not distort when hitting
obstacles in the ground8283.
Figure 32: Ground-mounted PV field with rammed post construction84
The results for specific demands of aluminium in the components are given in Table 26. According to our data, aluminium is used predominantly in construction (72% of total aluminium
input), followed by the input of aluminium to panel frames (22%), and finally aluminium in inverters (6%). Profiles for mounting are mainly made of aluminium due to its lighter weight.
Furthermore aluminium is recyclable and profile geometries are easier to meet system requirements. Although material input for construction/mounting structures could have been
saved these savings were compensated by the increase in material prices. In Germany, between 2005 and 2007 material input for construction was reduced by 50 kg/kWp while at the
same time costs increased from 130 Euro/kWp to 180 Euro/kWp, thus cheaper materials
might come into the market. PV systems can also be built with materials (e.g. wood) but material characteristics for wood (influence of weathering) are not as high when compared to
aluminium, even if treated with preservatives. Therefore there is no clear trend that might indicate an increase or decrease of aluminium use in PV technologies.
80
Federal Ministry of Environment, Germany (2007).
Federal Ministry of Environment, Germany (2007): p. 23.
82
Interview with Mr Heim, Mounting Sytems, 7 July 2010.
83
Interview with Mr. Grützner, Schletter, 12 July 2010.
84
Source: Solarenergie-Förderverein e.V.
81
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Table 26: Specific aluminium use in photovoltaic systems
Slanted roof panel
crystalline
Slanted roof laminate
Thin film
crystalline
Thin film
sc-Si
mcSi
a-Si
CIS
sc-Si
mcSi
ribbonSi
Inverter
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
Construction
60.9
64.5
131.1
79.6
-
-
-
PV panel/laminate
17.0
43.2
45.4
-
-
Total use of
aluminium in
kg per unit
81.2
67.9
177.6
128.
4
-
Total use of
aluminium in
kg /kW
27.1
22.6
59.2
42.8
-
Flat roof panel
Facade
crystalline
crystalline
Ground mounted
framed
module85
frameless
module86
CdTe
sc-Si
mc-Si
sc-Si
mcSi/
3.4
3.4
3.4
3.4
3.4
3.4
3.4
3.4
-
-
75.0
54.0
57.3
56.6
60.0
90.087
90.0
-
-
-
0.5
17.0
18.1
17.0
18.1
22.0
0.5
-
-
-
-
78.9
74.4
78.7
76.9
81.4
115.4
93.9
-
-
-
-
26.3
24.8
26.2
25.6
27.1
38.5
31.3
a-Si CIS
85
Average weight of 22 kg other PV panels has been considered.
Figure of frameless CdTe thin film laminate has been considered.
87
According to Bächler (2007) 120kg/kW of aluminium and steel are used in ground-mounted PV fields. As aluminium is lighter than steel 30 kg aluminum/kW is assumed, resulting in 90kg /3kWp (Source: Bächler (2007)).
86
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Aluminium and Renewable Energy Systems
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As neither figures for crystalline and thin film technologies nor figures for different construction types vary considerably, specific aluminium use is evenly analyzed for all subtechnologies.
The minimum specific aluminium use to be found is 23 kg/kW (Al minimum). Al maximum
is 59 kg/kW and Al moderate is set to be the average of all other technologies, being 32
kg/kW.
Table 27: Total use of aluminium in kg/kW
kg/kW
Al minimum
23
Al moderate88
32
Al maximum
59
3.3.4 Technology scenarios for photovoltaic systems
The technology scenarios for the future development of photovoltaic systems show a wide
range of assumed development pathways (see Figure 33).
in GW
Peter/Lehmann (2007), high
3'500
Peter/Lehmann (2007), low
3'000
MEF (2008)
2'500
Greenpeace (2008), low
2'000
Greenpeace (2008), high
1'500
EPIA (2006), reference
1'000
EPIA (2006), moderate
EPIA (2006), IEA reference
'500
IEA (2008a), ACT Map
'0
today
2020
2030
2040
2050
IEA (2008a), Blue Map
Figure 33: Technology scenarios for PV
In our analysis we assume for the SCENARIO BEST ESTIMATE that there will be growth
rates of 20 % until 2020, 10 % from 2020 until 2030 and 5 % until 205089. For SCENARIO
LOW a very pessimistic path is followed. Thus, the lowest projected installed capacity for
2020 is given by EPIA (2008), reference scenario and projects 33 GW. Greenpeace (2008),
low scenario projects 86 GW in 2030 and 153 GW in 2050. SCENARIO HIGH follows
Greenpeace (2008), high in 2020 with 269 GW, EPIA (2006), reference scenario with 1’272
GW in 2030 and MEF (2008) projections with 3’200 GW in 2050.
88
89
Average of AL minimum and AL maximum.
Frankl (2004): p. 45.
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Aluminium and Renewable Energy Systems
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The installed capacity today is set to 14 GW according to the newest report published by
IEA90.
Table 28: Study PATHs: installed capacity in GW
in GW
PATH LOW
PATH BEST ESTIMATE
PATH HIGH
today
14
14
14
2020
33
87
269
2030
86
225
1‘272
2050
153
597
3‘200
in GW
3'000
PATH HIGH
2'500
2'000
PATH BEST ESTIMATE
1'500
1'000
PATH LOW
'500
'0
today
2020
2030
2040
2050
Figure 34: Study PATHs
The produced electricity per year is based on 1’000 full-load hours on a global scale for
2010, which is a rather conservative estimate. Due to more efficient PV technologies full load
hours will increase by 5% until 2050 (see Table 29).
Table 29: Expectations of full load hours today and in future (worldwide average, rounded)
in h/a
2020
2030
2050
Photovoltaic systems
1’050
1’150
1’200
Consequently, electricity generation from photovoltaic systems will be between 21 TWh
(SCENARIO LOW) and 170 TWh (SCENARIO HIGH) for 2020 and between 100 TWh and
2’300 TWh for 2050. In comparison the global electricity generation in 2007 was 19’771
TWh.
90
IEA (2010): p. 9.
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Aluminium and Renewable Energy Systems
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Table 30: Energy production (in TWh, rounded)
in TWh
2020
35
2030
100
2050
190
SCENARIO BEST ESTIMATE
90
260
720
SCENARIO HIGH
280
1‘470
3‘880
SCENARIO LOW
For the calculation of the CO2 abatement potential, as described in chapter 3.2.4, a global
substitution factor is required. However it seems reasonable to use – as a conservative estimate – the factor derived for German conditions based on an analysis of power plant operation and marginal power plants (600 g CO2/kWh)91. Due to the production characteristics
(peak in noonday), a higher share of gas power plants is substituted compared to wind
power.
Today, the resulting CO2 abatement is about 8 Mt of CO2. In 2020 the abatement potential for
SCENARIO BEST ESTIMATE increases to about 55 Mt CO2. In 2030 and 2050 CO2 abatement will be 156 Mt and 430 Mt respectively (see Table 31). In spite of the higher substitution
factor and higher full load hours compared to solar thermal collectors the lower projected installed capacities photovoltaic systems lead to a lower CO2 abatement potential.
Table 31: CO2 abatement potential (in million tons, rounded)
in Mt CO2
2020
2030
2050
SCENARIO LOW
21
60
100
SCENARIO BEST ESTIMATE
55
156
430
SCENARIO HIGH
170
880
2‘300
3.3.5 Resulting current and future aluminium use in photovoltaic sytems
Using the scenario assumptions defined above, the SCENARIO BEST ESTIMATE projects a
total aluminium use in PV systems of 3 Mt in 2020, 7 Mt in 2030, and 19 Mt in 2050.
SCENARIO LOW indicates a total aluminium use of 1 Mt in 2020 and 4 Mt in 2050 (Table
32). SCENARIO HIGH shows a total aluminium use of 16 Mt in 2030. Total maximum aluminium use in 2020 and 2030 will be 75 Mt and 189 Mt.
Especially when compared to the technologies examined so far the latter figure is very high.
This has to do with the optimistic technology diffusion assumptions of the circumstances that
constitute this scenario.
If installation rates are assumed to be as in Scenario Best Estimate and aluminium use is assumed to be Al maximum, aluminium use could be almost doubled in the reference years
(Scenario Best Estimate  Scenario Best Estimate Plus).
91
CO2 abatement factor is set to 0.6 kg CO2/kWh, which is slightly higher than 0.591 kg CO2/kWh
mentioned by German Federal Ministry of Environment (Federal Ministry of Environment, Germany
(2009): p. 24).
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Aluminium and Renewable Energy Systems
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Table 32: Quantification on future total use of aluminium for reference years
in million tons (Mt)
2020
1
2030
2
2050
4
SCENARIO BEST ESTIMATE Minus
2
5
14
SCENARIO BEST ESTIMATE
3
7
19
SCENARIO BEST ESTIMATE Plus
5
13
35
SCENARIO HIGH
16
75
189
SCENARIO LOW
To get an approximation on the size of development of the annual aluminium market for PV
systems, the total aluminium use per decade is calculated (see Table 33). As seen in these
figures from all scenarios the biggest market sales potential of aluminium is given in decades
2021-2030 and 2031-2050. For example, in the SCENARIO BEST ESTIMATE aluminium
use is highest in 2031-2050 with almost 0.6 Mt per year. In this decade, annual aluminium
use accounts for approximately 1.6 % of annual aluminium production. If aluminium were to
be used to a broad extent annual aluminium use could even be 4.7 % in 2050 (Al moderate
 Al maximum as in SCENARIO BEST ESTIMATE Plus).
Table 33: Total and annual aluminium use (in tons and as percentage of annual global aluminium production)
Annual Al use
in decade in
tons
Annual Al use as percentage of annual Al production92 (rounded)
2010-2020
44‘000
0.12
2021-2030
122‘000
0.33
2031-2050
77‘000
0.21
2010-2020
150‘000
0.4
2021-2030
360‘000
1.0
2031-2050
500‘000
1.4
2010-2020
233‘000
0.64
2021-2030
442‘000
1.21
2031-2050
595‘000
1.63
2010-2020
466‘640
1.3
2021-2030
1.280‘000
3.5
2031-2050
1‘700‘000
4.7
1‘505‘000
4.13
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
SCENARIO HIGH
2010-2020
92
Annual production: 36,400,000 tons (Source: IAI 2010).
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Aluminium and Renewable Energy Systems
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2021-2030
5‘918‘000
16.26
2031-2050
5‘688‘000
15.63
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3.4 Solar cookers
Solar cookers are devices that concentrate solar radiation in a focal point where a dark container absorbs heat from sun rays in order to heat the container’s content. Solar cookers are
qualified for boiling water, warming up food, frying, baking or roasting.
3.4.1 Description of technologies
There are different types of solar cookers (see Figure 35): Box cookers are insulated boxes
that capture both direct and diffused solar radiation. Mirrors are laterally attached to allow
more sunlight to enter through the glass top. Therefore a frequent manual re-positioning facing the sun is not needed. Depending on the design and the temperature of the surrounding
air, temperatures of over 100 °C can be reached (no frying or roasting is possible). The box
cookers must be closed during cooking, which makes stirring or adding of ingredients impossible. Therefore, the solar box cooker can be used only for basic cooking (for example to
prepare rice or lentils). Box cookers consist of two boxes. The outer box is made out of
wood, plastic or metal and the inner box is made out of aluminium sheets93.
Figure 35: Example of solar cookers: box cooker (top left), panel cooker (top right), panel cooker with
aluminium panels (bottom)94
Panel solar cookers consist mainly of reflecting panels which are made from cardboard with
aluminium foil adhered to it or cardboard that already contains an aluminium coating (e.g.
93
Interdepartementale Plattform zur Förderung der erneuerbaren Energien und der Energieeffizienz
in der internationalen Zusammenarbeit (without year): p. 6.
94
Sources: Applied Solar, Ecofriend.org, SolarcookeratCantinaWest.
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used Tetra-Pak wrapping)95 though some are made of aluminium sheet. The focus of the
panels is the pan so to prevent the pan from losing its heat, the pan is put in a transparent
and heat resistant plastic bag that have a limited lifetime. As with the box cooker, the heat is
lost when the bag is opened which prevents any intervention in the cooking process for stirring or adding of ingredients. Temperatures can reach just over 100 degree Celsius.
Solar parabolic cookers have a reflecting surface in the form of a parabolic dish, which concentrates the solar rays at a focal point at which the black coated cooking pot is placed. High
temperatures, well over 150 degrees Celsius, can be reached when the cooker is well positioned towards the sun. The cooker needs to be repositioned towards the at least every 15
minutes. In contrast with the solar cooking box however, cooking times can be similar to traditional stoves. Solar parabolic cookers consist of a galvanized steel or metal frame, with a
wooden frame being use in rare cases96. Reflector panels are attached to the frame and consist of aluminium or steel. Additionally an extra ceramic layer exists to prevent weathering.
These solar cookers weigh 20 kg or more with a steel frame or around 12 kg with an aluminium frame97.
Figure 36: Solar parabolic cookers98
(Automatic) solar parabolic cookers or so called Scheffler solar kitchens are bigger consisting
of one or more solar dishes (each 2 to 16 square meters). The concentrating reflectors track
the movement of the sun, reflecting the light of the sun and concentrating it on a fixed position. In some configurations the reflected and concentrated sunlight enters a nearby kitchen
directly to strike a cooking pot or frying surface. In other configurations, the concentrated
sunlight is used first to create steam which is transported by pipes to a nearby kitchen. These
solar kitchens reach very high temperatures. This technology is very cost-intensive and is
primarily installed in India. The structure of the reflector is made from steel or aluminium and
95
ibd.
Interdepartementale Plattform zur Förderung der erneuerbaren Energien und der Energieeffizienz in
der internationalen Zusammenarbeit (without year): p. 12.
97
Source: Sun and Ice 2010 pricelist.
98
Source: EG Solar.
96
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is flexible. Fixed, non-mobile devices are equipped with glass mirrors while mobile devices
are equipped with aluminium sheets99.
Figure 37: Solar community kitchen100
3.4.2 Current market situation for solar cookers
Exact global figures for solar cookers in use today are not available in the literature. Several
small scale projects exist worldwide which list the dissemination of solar cookers for their
project. In order to get an approximate first overview of global capacity it is therefore necessary to look at sales figures from main manufacturers (see Table 34).
Table 34: Sales101 Company
Integrated Logistics Sotutions,
S.A. de C.V.
(ILS), Mexiko
SunFire, South
Africa
Solar Oven Society, USA
Sun Oven International,
USA
Name of solar cooker
model
Hot Pot
price
remarks
USA: 99$US
Hot Pot is sold mainly in Mexico, but is exported to US and Europe. Several thousands
of solar cookers have been produced.
SunFire14,
SunFire10
South Africa
2000R, 1500R
Sales around 500 a year.
SPORT
USA: 125$US
-
Global Sun
USA: 279$US
Thousands of solar cookers have been sold.
99
Interdepartementale Plattform zur Förderung der erneuerbaren Energien und der Energieeffizienz in
der internationalen Zusammenarbeit (without year): p. 13.
100
Source: Indiamart.
101
Interdepartementale Plattform zur Förderung der erneuerbaren Energien und der Energieeffizienz
in der internationalen Zusammenarbeit (without year): p. 49.
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Solar cookers
international,
USA
Müller Solartechnik,
Germany
Cookit
USA: 25$US
Kundu Kaar,
Zèbre,
Primerose
Alsol, Spanien
Sun Co SA,
Portugal
Alsol 14
SunCook
Germany Kundu
Kaar 80€,
Zèbre 140€,
Primerose 285€
Spain: 260€
Europe: ca. 300€
Yancheng
Sangli Solar
Energy,
China
Butterfly
1050$ US for 10
pieces in export;
in China: 65$US.
Fair
Fabricators,
India
Rohitas Electronics, India
-
India: 50 $US
Tulsi cooker
USA: 307$US
unknown, China
EG Solar e.V.,
Germany
Sun and Ice
GmbH,
Germany
Ico-GE
Spain: 85€
SK14, SK11
298 - 378€
Premium11,
Premium14
Germany: 239€
(1,1m),
279€ (1,4m)
SCI is the umbrella organization for solar cooking. It sells different solar cookers, and produces the simplest of all cookers, Cookit.
Small manufacturer from Germany which has
been in business for five years. Sales are
around several hundred a year.
Target 2009 was 800 solar cookers.
Model made fully out of plastic. Sucessful distribution via idCook, France.
Sales mainly in China. The model Butterfly is
rather heavy because it is manufactured from
steel (50 kg). Producer estimates having sold
1.8 million units since 1983 and 80,000 units
per year.
Producer estimates: sold 100,000 units in last
20 years.
The only solar cooker on the market with electrical backup. On the market for 25 years. Annual sales of 5,000 solar cookers.
Discount model with poor quality.
Inventor of SK 14 model. Sold 50,000 units
within the last 20 years.102
Commercial branch of EG Solar. Has sold
14,000 solar cookers within the last five years.
Estimates for China show that 1.4 million have been sold so far103. Figures for China, however, must be regarded carefully and as very uncertain, e.g. manufacturer Yangcheng estimates having sold 1.8 million units alone.
India as well produces very high figures of 75’000104 and 100’000105 solar cookers sold every
year. Another figure estimates 500’000 units that have been sold in India106.
The Deutsche Gesellschaft für technische Zusammenarbeit estimates that 900‘000 solar
cookers have been sold worldwide until 2002, most of them in Asia (95 percent)107108.
102
Interview with Mr Michelbauer, EG Solar, 21 June 2010.
Xiaofu (2009).
104
Mahalingam (2006)..
105
Maithani (2009).
106
Gadhia (2009).
107
Interview with Ms Feldmann, HERA - Poverty-oriented basic energy services, GTZ, 16 March 2010.
108
GTZ (2002).
103
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3.4.3 Specific aluminium use in solar cookers
Solar parabolic cookers usually come with a steel or aluminium metal pedestal frame. The
reflecting material of the solar cooker can be made from a plain full material (most common
is aluminium) or a plain material with an additional reflecting layer. These materials show different reflectance characteristics.
Table 35: Reflectance of different materials used for solar cookers
Reflecting materials
Reflectance
Clear/transparent glass
94%
Common glas
80%
Polished plain aluminium
84%
Coated foils/film
80-75%
Although clear/transparent glass proves to be the most effective material, it is difficult to obtain in developing countries109. Common glass (thickness: 2 mm) is more widespread and
does not lose effectiveness when maintained regularly. Although, in order to get an optimal
focal point, assembling of small glass facets is necessary because glass cannot be bent.
Even today it is difficult to form glass into the desired shape with the degree of accuracy required. For instance it is preferred that the curve of parabolic reflectors be accurate to within
one tenth of a degree. Unfortunately this degree of accuracy is currently not available110 especially not in developing countries.
Furthermore glass facets are fragile, showing shorter life times111. Today this technique is still
in use, mainly in China, which has the advantages of good friction resistance, slick surface,
reasonable price and a moderate four to five year life-span112. It is, however, vulnerable to
erosion, desquamate, metamorphose, and cost time and labour for replacing the slick surface. Aluminium film, with characteristics of high reflectance and easy replacement and a lifetime of only 2-3 years, was used for the recently produced commercialized solar cookers.
Coated foils/films are spanned and adhered firmly onto a metal frame. Weathering of the
glue is one disadvantage, another one is the blinding of the foil113. Solar cookers using synthetic reflecting layers like (optical polyester; example solutions from idCook, France114) show
good intensity and rigidity, and are very light, which can meet the demand of the general
109
Tyroller (2004): p. 23.
United States Patent 4238265: Method of manufacturing a glass parabolic-cylindrical solar collector.
111
Garg et al. (2000): p. 306.
112
Interview with Mr Veit, EG Solar at Intersolar, 12 June 2010.
113
Tyroller (2004): p. 24.
114
e.g. idCook solar cookers consist only of a negligible amount of aluminium per square meter; Total
weight: 6.5kg; about one 1g/m² aluminium (Source: Interview with Mr Basilhet, idCook, at Intersolar,
12 June 2010).
110
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transportation; plus they are very cheap115. The disadvantage of this solar cooker is less resistance and that cleaning causes abrasion and subsequently loss in reflectivity116.
Metals cannot be polished in order to be reflective enough for solar cooking. One exception
though is anodized aluminium. Aluminium solar cookers show good shape maintenance but
their disadvantage is that they become blind in proximity to salt water. This kind is the most
widely used especially for the economically moderate price, easy shaping, and simple technique117. Polished aluminium is easy to deal with and assemble. Improper cleaning of the
surface leads to scratches and consequently to a reduction of reflective effectiveness118.
Alanod, a German manufacturer for aluminium sheets produces a variety of aluminium
grades. It does market one product line specifically for solar applications with reflectivity
grades of 85-95%119. Aluminium products that are expected to last for extended periods of
time must be covered with a protective coating.
Currently there are two types of material for reflection layers in use glass mirror and aluminium film. The latter is prone to weathering. Full-material solar cookers do not necessarily
need reflecting material, especially when made of aluminium which shows high reflecting
characteristics.
For this study a full material solar parabolic cooker was chosen as the reference technology
because this technology is regarded as a common market available technology120. Additionally its costs are moderate, and net power, cooking temperatures and life span characteristics are adequate due to its nano-ceramical protection layer. Finally these solar cookers have
the advantage to being easily manufactured on-site.
With this reference solar cooker the following specific aluminium use is assumed. 20 kg of
aluminium can be found in a model in which the whole apparatus (frame, reflector) is made
of aluminium (Al maximum)121. Al moderate is estimated with a share of 3 kg of aluminium
per solar cooker unit, whereas aluminium is used in reflectors122. It consists of reflector
sheets made from highly reflective aluminium (anodised, hard, high reflecting aluminium
sheet, 0.5 mm thick). These reflectors are fixed to a parabolic shaped metal frame. Al minimum is estimated to be 0.1 kg per unit if nearly no aluminium is used at all123.
Table 36: Aluminium use in solar cookers
Total
Al minimum
Al moderate
Al maximum
0.1 kg
3 kg
20 kg
115
Interview with Mr Basilhet, idCook, at Intersolar, 12 June 2010.
Interview with Mr Michelbauer, EG Solar, 21 June 2010.
117
Interview with Mr Michelbauer, EG Solar, 21 June 2010; Interview with Mr Veit, EG Solar at Intersolar, 12 June 2010, Interview with Mr Basilhet, idCook, at Intersolar, 12 June 2010.
118
Tyroller (2004): p. 24.
119
Reflective 85, MIRO Reflective 90, MIRO high reflective 95.
120
Interview with Mr Michelbauer, EG Solar, 21 June 2010; Interview with Mr Veit, EG Solar at Intersolar, 12 June 2010, Interviwe with Mr Basilhet, idCook, at Intersolar, 12 June 2010.
121
Model SK 14 (full equipment) from EG Solar, EG Solar 2010.
122
Sun and Ice SK 14 model; Interview with Mr Michelbauer, EG Solar, 21 June 2010.
123
idCook Cook up 200 made mainly of optical polyester and wood; Interview with Mr Basilhet, idCook, at Intersolar, 12 June 2010.
116
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3.4.4 Technology scenarios for solar cookers
As opposed to the other renewable energy technologies focused on and due to the fact that
no expansion scenario is available for the reference years 2020, 2030 and 2050, only the
overall potential of solar cookers that can reasonably be installed in the future will be focused
on hereafter. Solar Cookers International has compiled a list of twenty countries with the
highest potential for solar cooking. Criteria for this ranking include annual average sunlight,
cooking fuel scarcity and population size. Of the estimated 500 million people who have
abundant sunshine and suffer from fuel scarcity, 85 % of them live in a few countries124.
Table 37: Focus countries for solar cookers
Focus countries for solar cookers
India
China
Pakistan
Ethiopia
Nigeria
Uganda
Sudan
Afghanistan
Tanzania
South Africa
Niger
Somalia
Brazil
Kenya
Nepal
Mozambique
Burkina Faso
Madagascar
Malawi
Zimbabwe
For an estimation on the overall market potential of solar cookers, it has to be assessed how
many people could use solar cookers instead of other systems:
In developing countries, especially in rural areas, 2.5 billion people rely on biomass, such as
wood, charcoal, agricultural waste and animal dung to meet their energy needs for cooking125. In the absence of new policies the number of people relying on biomass will increase
to over 2.6 billion by 2015 and to 2.7 billion by 2030 because of population growth126. Two
complementary approaches can improve this situation: 1) promoting more efficient and sustainable use of traditional biomass, 2) encouraging people to switch to modern cooking fuels
and technologies. Halving the number of households using traditional biomass for cooking by
2015 – a recommendation of the United Nations Millennium Project – would involve 1.3 billion people switching to other fuels or cooking systems.
Experts estimate that solar cookers could be used by 1 billion people worldwide127. Other experts say that the economical potential of solar cookers worldwide is at least 167 million solar
cookers128. The latter estimate seems to be reasonable, but approximations of 1 billion people or more seem to be unreasonably high therefore an own estimate was calculated129:
According to other sources 500 million people have abundant sunshine and suffer from fuel
scarcity, a prerequisite for switching to solar cooker technology. It is assumed that one solar
cooker serves 6 people. Consequently, the market potential consists of around 83 million so124
Blum (2009): p. 1.
GTZ (2007): preface.
126
Note: About 1.3 million people – mostly women and children – die prematurely every year because
of exposure to indoor air pollution from biomass.
127
Interview with Mr Michelbauer, EG Solar, 21 June 2010.
128
Lardy (2006).
129
Calculation on the basis of Seifert (1999): Proposals for a Global Solar Cooker Programme.
125
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lar cooker units. It is assumed that an average of 1’000 solar cookers are produced annually
in one workshop, and 2’000 workshops/manufacturers exist.
Therefore two million solar cookers could be produced every year and it would take approximately 42 years (approximately: year 2050) to equip all the above mentioned 500 million
people with solar cookers. Subsequently 83 million units are considered to be PATH BEST
ESTIMATE, 167 million units mark PATH HIGH and PATH LOW is set to 10 million solar
cooker units by default.
The primary energy that is used for cooking varies strongly from region to region. A consideration of a regional specific primary energy mix could not be undertaken within the scope of
this study. In order to obtain an estimate on CO2 abatement potential of solar cookers worldwide small scale projects and especially CDM projects have been examined. CO2 abatement
potentials for a single cooker per year are listed in Table 38.
According to the projects examined, annual CO2 savings are within a span of 0.8 t (Solar
Cooker CO2 abatement potential Minimum) to 3.7 t (Solar Cooker CO2 abatement potential
Maximum) of CO2 per solar cooker per year. This corresponds well to the assumptions of
other experts130. Solar Cooker CO2 abetment potential moderate is the average of CO2
abatement potential of a solar cooker per year in examined projects, namely 2.5 t.
Table 38: Solar cooker projects and annual CO2 abatement potential per solar cooker in tons Project
CDM Solar Cooker Project, Indonesia (Aceh)131
Federal Intertrade Pengyang Solar Cooker Project, China132
Ningxia Federal Solar Cooker Project, China133
Federal Intertrade Hong-Ru River Solar Cooker Project,
China134
Federal Intertrade Haiyuan Solar Cooker Project135
Project in Chad136
Project in Nepal137
South Africa solar cooker project138
Average
Annual CO2 abatement potential per solar cooker in tons
3.5
2.1
2.1
2.1
2.0
3.7
3.3
0.8
2.5
CO2 abatement potential for solar cookers in Mt for the three different PATHs is shown in Table 39.
130
Personal information of Mr Seifert, EG Solar.
UNFCCC CDM project.
132
UNFCCC CDM project.
133
UNFCCC CDM project.
134
UNFCCC CDM project.
135
UNFCCC CDM project.
136
Krämer (without year): p. 8.
137
Shrestha (without year): p. 2.
138
Hancock et al. (2006): p. 21.
131
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Table 39: CO2 abatement potential for solar cookers in million tons (Mt)
CO2 abatement potential for solar cookers
in million tons (Mt)
SCENARIO LOW
8
SCENARIO BEST ESTIMATE
208
SCENARIO HIGH
618
3.4.5 Resulting current and future aluminium use in solar cookers
Based on these assumptions, the SCENARIO BEST ESTIMATE leads to an overall specific
aluminium use of 249’000 t until 2050. Compared to the above mentioned technologies, figures even in SCENARIO HIGH are rather low. Nevertheless, especially with regard to CDM
projects, solar cookers could be a favourable technology for aluminium use.
Especially noteworthy is that moving from Al moderate to Al maximum increases market potential by five times (see SCENARIO BEST ESTIMATE Plus).
Table 40: Overall aluminium use in solar cookers
in t
Overall aluminium use in solar cookers
SCENARIO LOW
1
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
8‘300
249‘000
1‘660‘000
SCENARIO HIGH
3‘340‘000
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3.4.6 Solar community kitchens (excursion)
The basic idea of this technology is that the concentrating reflectors track the movement of
the sun, reflecting the light of the sun and concentrating it on a fixed position. In some configurations the reflected and concentrated sunlight enters a nearby kitchen directly to strike a
cooking pot or frying surface. In other configurations, the concentrated sunlight is used first to
create steam which is transported by pipes to a nearby kitchen.
Figure 38: Scheffler community kitchen139
This technology is also well known as Scheffler solar kitchen technology and is named after
German Wolfgang Scheffler who built the first well-functioning Scheffler-Reflector) in 1986 in
Kenya. Since then the technology has been continuously improved. For a number of years
mainly 8 m² size reflectors were constructed for canteen kitchens. After 2000 mostly 10 m²
and 16 m² Scheffler-Reflectors were installed140.
It is difficult to approximate how many Scheffler Reflectors exist since there is no central registration and many workshops work independently. In 2004 there were about 750 reflectors in
21 countries, which corresponds to about 200 solar kitchens, including 12 solar steam kitch139
Source: Barli.org.
Information from Solare Brücke website; see: http://www.solare-bruecke.org/English/scheffler_eDateien/scheffler_e.htm; last accessed: 20 July 2010.
140
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ens with 10 to 106 reflectors per installation. In 2006 it was estimated that around 950 Scheffler Reflectors were installed worldwide141.
Estimation on installed capacity of solar community kitchens
According to experts there are today 2’300 solar reflectors with an average size of 10 m² and
16 m² worldwide. Half of the 2’300 solar reflectors have 10 m² (=11’500 m² installed capacity)
and the other half have a 16 m² reflector (= 18’400 m² installed capacity)142. Most of the solar
community kitchens are found in India143 Including the world’s largest solar kitchen set up in
Taleti, India. The food is cooked in 200-400 liters cooking pots, producing an average of
20’000 meals a day and up to 38’500 meals per day during periods of peak solar radiation
maximum.
Current use of aluminium in solar community kitchens
Reflectors are primarily made from reflecting glass and for the mounting structure steel is
used144. Aluminium is to be found in aluminium profiles which bear the reflectors. Therefore,
flat and E-profiles made of AlMgSi alloy are used. An estimated 20 kg of aluminium is used
for an 8 m² reflector145, resulting in 2.5 kg per square meter. As almost 30’000 m² of solar
kitchens exist, 75 tons of aluminium are currently processed in those systems.
Future perspective of aluminium use in solar community kitchens
During our research no scientific reliable figure on future perspectives could be found. While
one expert estimates a slight increase in installed capacity, another expert argues that bigger
solar community kitchens based on solar reflectors have the potential to be replaced by CSP
technologies (e.g. parabolic trough systems) because the generation of heat will be
cheaper146. If parabolic trough technology should gain momentum to serve as a provider of
heat for community kitchens, then aluminium use for this technology would increase147.
141
Information from Solare Brücke website; see: http://www.solare-bruecke.org/English/scheffler_eDateien/scheffler_e.htm; last accessed: 20 July 2010.
142
Interview with Ms Hoedt, assistant of Wolfgang Scheffler, 1 July 2010.
143
Interview with Mr Veit, EG Solar at Intersolar, 12 June 2010.
144
Information from Solare Brücke website; see: http://www.solare-bruecke.org/English/scheffler_eDateien/scheffler_e.htm; last accessed: 20 July 2010.
145
Interview with Ms Hoedt, assistant of Wolfgang Scheffler, 1 July 2010; own calculations.
146
Interview with Mr Michelbauer, EG Solar, 21 June 2010.
147
Interview with Mr Michelbauer, EG Solar, 21 June 2010.
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3.5 Concentrating Solar (Thermal) Power (CSP)
Concentrated solar power (CSP) or solar thermal power plants use concentrated sunlight to
generate electricity or heat by using high temperatures. CSP power generation is generally
divided into four types: solar fields, solar towers, solar dishes and concentrating photovoltaic.
3.5.1 Description of technologies
Solar fields are the most common type to generate CSP, but all types of CSP have the same
principle for generating electricity (see Figure 39): Solar radiation gets concentrated by a
concentrator (e.g. troughs, a central receiver or a dish-sterling) to heat a transfer fluid (e.g.
oil, molten salt, water or air). The heat then can be channelled to and stored in a thermal
storage system (molten salt, PCM148, concrete) or can be directly converted to electricity. The
advantage of these technologies is the possibility that, especially in combination with storage
systems, electricity is available when the sun does not shine. Within this combination storage
of 7.5 hours for solar fields and 16 hours for solar towers is possible and currently being
practice. Another usage of this technology is co-generation for cooling or desalination.
Solar field
Solar tower
Solar dish
Concentrated PV
Figure 39: Concentrating Solar Power technologies (top left: solar field Andasol I, Spain; top right: solar tower Solar Two, USA; bottom left: Stirling Energy Systems Concentrator Dish; bottom right:
SolFocus 1100 system)149
148
PCM = Phase Change Materials.
Sources: Estelasolar, Global-greenhouse-warming.com, Solarcentral.org,
Worldofphotovoltaics.com.
149
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Solar fields
Sun rays are collected in a trough and passed to a receiver in the middle of the mirror. Normally there are two different types of troughs: parabolic troughs and Fresnel reflectors.
The parabolic troughs concentrate sunbeams directly through an absorber which is filled with
thermo oil that is needed to generate steam. This steam can be used to generate electricity
with the use of a conventional steam turbine and a generator. The plants can be equipped
with a tracking mechanism to use the maximum sunlight at any given time. The efficiency of
these plants is above 20%. Parabolic troughs are the oldest method of CSP, with the first
troughs being used in the SEGS (“solar electricity generation systems) which were built in
California during the 1980’s.
Fresnel collectors consist of several flat mirrors that direct sunlight indirectly through a secondary concentrator to the absorber, which is filled with water that evaporates and thereby
generates electricity via a steam turbine. The flat mirrors have only one axis which reduces
the production costs in comparison to parabolic troughs. The disadvantage of Fresnel collectors is that the efficiency is lower so therefore Fresnel collectors need a bigger field area to
produce the same electricity as parabolic troughs.
In summary the lower efficiencies get compensated through the lower production costs.
Fresnel troughs are beneficial in unsettled regions where land use only plays a minor part
(e.g. desert regions). In comparison parabolic troughs are advantageous in regions where
land use has a significant influence on the living standards. Another advantage of Fresnel
collectors is that the collectors are suitable to spent shadow under their construction area.
This is an opportunity for usage on agricultural areas to protect plants from direct solar radiation.
Solar tower
A solar tower consists of a central receiver located at the top of a tower. Independently operating heliostats (mirrors) build a field around the tower and concentrate the solar radiation to
the receiver that usually consists of a ceramic membrane. With this technology temperatures
of over 1’000 degrees Celsius can be reached. The energy transportation and storage
(through steam, molten salt, air, etc.) is much easier and the energy efficiency is higher than
in solar fields because the concentration and energy conversion is fixed in one point. Actually, energy from solar towers can be stored over a period of 15 hours. That is two times
higher than the storage possibilities of solar fields (about 7.5 hours)150.
150
Estella (2009): p. 23.
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Figure 40: Types of CSP technologies151
Solar dishes (or stirling dishes)
Solar dishes consist of one big parabolic trough that concentrates the solar radiation to one
point in the middle of the dish. There, an engine (stirling motor) converts heat to electricity or
heat of different dishes can be transported into a central power engine where a stirling engine generates electricity. Normally solar dishes have a capacity of 5 to 50 kW.152 But dishes
beyond 100 kW are planned or are under construction.
Because of the low capacities of solar dishes, in comparison to other CSP technologies, and
a feasible possibility to store the energy there is no mass market. Only a few demonstration
systems are actually running. Therefore, solar dishes are practical for a decentralized use in
regions where no grid connection is possible or an additional use through an insufficient grid
is needed.
Concentrating Photovoltaics (CPV)
The principle of Concentrating Photovoltaic systems is different than other technologies mentioned in this chapter. While solar fields, dishes and towers use the concentrated sun radiation to generate heat, CPV tries to avoid thermo dynamical processes. The sun radiation gets
concentrated (mostly through Fresnel lines) but the concentrated radiation gets immediately
directed through PV cells behind the lenses. In comparison to normal PV cells the radiation
has a much higher concentration (between 10 and 2’000 times153) and is therefore more ef151
Source: Greenpeace (2009): p. 16.
Viehbahn (2008): p. 10.
153
According to Pihl (2009): p. 17.
152
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fective. CPV systems use triple junction PV cells, normally operate between 5 and 100 kV
and can work with an efficiency of 40%.
3.5.2 Current market situation for CSP
The idea of using solar energy in large power plants is not new. At the beginning of the 20th
Century a solar field was built in Shuman (Egypt) with a capacity of 55 kilowatts. But because
of low energy prices and high costs for power generation development stagnated a long time.
In the 1980’s a total of nine power plants (SEGS = “solar electricity generation systems”)
were built in California (USA) which have a total capacity of 354 MW. The two biggest solar
thermal power plants in Europe (Andasol I-II) are located in southern Spain and feature a capacity of 50 MW each. Another identical solar field (Andasol III) with the same capacity is already under construction. Despite the fact that the technique was already well known the
large increase of solar thermal power plants in the market only took place during the last five
years. Today a total of 516 MW are installed worldwide (2009)154.
Installed capacity worldwide
In comparison to other renewable energy technologies (wind, PV, solar thermal power, biomass) concentrated solar power (CSP) is still a niche technology. The installed capacity is
516 MW worldwide. Divided into technologies, parabolic troughs prevail with an installed capacity of 468 MW (90.2% of the total installed capacity in 2009 and 15,798 GWh produced
electricity). Solar towers had a capacity of 44 MW (8.5 % of the total capacity) in 2009. Fresnel troughs only had a capacity of 4 MW (0.8 % of the total capacity and 10 GWh produced
electricity). Solar dishes only worked in demonstration projects with a total capacity of 0.24
MW (3 GWh produced electricity)155.
Also interesting is the capacity that is planned or under construction. Here the capacities vary
significantly from the already installed capacities. A total capacity of 9’658 is planned or under construction. The share is 4’449 MW (46%) of parabolic troughs, 3’026 MW (31%) for solar towers, 483 MW (5%) of Fresnel troughs and 1’700 MW (18 %) of solar dishes156 (see
Table 41).
Table 41: Installed and planned capacity and electricity generation of CSP technologies
Technology
Installed capacity
in 2009 (in MW)
Parabolic troughs
Produced electricity in 2009 (in GWh)
Planned capacity or under construction (in GW)
468
15’798
4’449
Fresnel troughs
4
10
483
Solar towers
44
83
3’026
Solar dishes
0.24
3
1’700
154
Greenpeace (2009): p. 16.
Greenpeace (2009): p. 16.
156
Greenpeace (2009): p. 16.
155
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Installed capacity by regions
For CSP technologies it is necessary to have constant high solar radiation. Therefore most of
the regions of the world are not qualified. Only the regions which lie in the sun belt of the
world (20 and 40 degrees latitude north and south) are suitable for CSP technologies. There
the solar radiation is much higher than in the rest of the world; a significant condition to make
CSP technologies profitable. Regarding Europe, only a few regions can fulfil these conditions
namely parts of the Mediterranean area of Europe especially in southern Spain. One third of
the planned capacity and capacity under construction worldwide is being realized in Spain157.
Excellent conditions are also found in Africa, especially Northern Africa, in Australia, in the
Southern United States and in parts of the middle of South America.
Key manufacturers and market actors
Solar fields
The Solar Energy Generating Systems (SEGS) were produced by Luz II Ltd. (which is actually a subsidiary of BrightSource Energy) in the 1980’s. The operating company of the SEGS
is FPL Energy (a subsidiary of the FLP Group). The SEGS receivers were built by the German company Schott AG. The SEGS are the biggest currently installed CSP plants with a total capacity of about 354 MW158.
The Andasol Concentrating Solar Power plants (Andasol I+II in operation; Andasol III under
construction) are located in Granada in Southern Spain and were developed and produced
by the German company Solar Millenium. About 75% of the plants are in possession of the
Spanish construction company Grupo Cobra (a subsidiary of Grupo ACS). The other 25%
are in possession of Solar Millenium. Flagsol GmbH, a subsidiary of Solar Millenium, is responsible for the operation of the plants. Each of the three identical plants has a capacity of
50 MW159.
Another big concentrating solar power field in Boulder City (Nevada, USA) is under construction. Solargenix is the prime contractor of this 64 MW plant. In Israel a 150 MW facility (with
the option of an expansion to 500 MW) is operated by the company Solel160.
A power plant using Fresnel technology has been near Sidney, Australia, since 2004. The
University of New South Wales has developed this technology which has a total capacity of
15 MWth and runs in co-generation with a coal plant to generate steam.
Two other Fresnel based power plants are located in Sevilla (Spain, 176 kW, PSE) and in
Karlsruhe (Germany, 1.4 MW, Novatec Biosol). The former is used for the cooling system of
the local university. The latter is used to produce solar steam for a coal plant.
157
Fraunhofer ISI, ITZ (2009): p. 155.
For more information: www.flp.com
159
For more information: http://www.solarmillennium.de/
160
For more information: http://thefraserdomain.typepad.com/energy/2005/09/about_parabolic.html
158
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Solar towers
In Sevilla (Spain) a tower was built in 2007 with a capacity of 11 MW. In 2009 the plant was
complemented by a second tower with a capacity of an additional 11 MW. The two towers
(called PS10 and PS20) are operated by the Spanish company Abengoa and are part of big
solar park of different CSP technologies with a total capacity of 302 MW.
CESA-1 and SSPS-CRS are two solar towers located on a test field in Almería (Spain) that
use Fresnel technology. They have a capacity of 7 MW and 1.2 MW. In the United States
“Solar Two” is the biggest current running solar tower. It is located in California and has a
capacity of 10 MW. In Jülich (Germany) the first German demonstration and development of
a solar tower was started in 2006 and has been running in test mode since 2009 with an approximate capacity of 1,5 MW161.
Solar dishes
As mentioned earlier, there is no market for solar dishes. Only some test projects generate
solar energy but these systems do not run on a commercial basis. With regard to the future,
interesting projects are being planned at the moment, e. g. Stirling Energy Systems (SES)
plans in cooperation with the Sandia National Laboratories a solar field of over 70,000 dish
engine units in San Diego. In 2014 the field should have a capacity of 750 MW and supply
about 562,500 households with energy162.
3.5.3 Specific aluminium use in CSP technologies
Concerning CSP technologies, aluminium use today and in future for those technologies has
to be considered with great care. Depending on the future development with a variety of different factors (e.g. investments in R&D, grid connection developments, national and international policy and many more) aluminium might play a significant role. On the other hand,
aluminium could also play a subordinate role if development moves into other directions.
The optimal location for CSP technologies is in regions where the sun radiation during the
year is high. These regions are mostly in deserts and dry areas in the sun belt of the world.
But most of the suitable regions have no or only a slightly developed infrastructure where
production and transportation of CSP components for power plants are difficult to handle.
Component materials (reflector systems and supporting structure) have special requirements
for an efficient usage in CSP technologies:







161
162
low costs
corrosion resistance (sand storms in desert regions and salt deposit in coastal regions)
mechanical resistance (periodical washing)
high solar reflectivity
low weight (transportation)
high stiffness (of frames to carry the reflectors)
a simplified assembly line (less developed infrastructure)
For more information: Solarinstitut Jülich (http://www.fh-aachen.de/index.php?id=378)
For more information: http://www.sandia.gov/LabNews/100507.html
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To give detailed information about current and future aluminium use life cycle assessments
(LCA) of the current technologies on the market and those technologies that have a potential
to play a significant role in future have been examined. The analysis was completed with expert interviews of different component manufacturers and plant operators of CSP technologies. LCA’s and studies which were used to analyze CSP technologies are:
-
ANGERER, G./ERDMANN, L./MARSCHEIDER-WEIDEMANN, F./SCHARP, M./LÜLLMANN, A./
HANDKE, V./ MARWEDE, M. (2009): Rohstoffe für Zukunftstechnologien: Einfluss des
branchenspezifischen Rohstoffbedarfs in rohstoffintensiven Zukunftstechnologien auf
die zukünftige Rohstoffnachfrage. Karlsruhe, Germany.
-
EUROPEAN COMMISSION (ed.) (2009): Environmental and ecological life cycle inventories for present and future power systems in Europe (ECLIPSE): Life Cycle Inventories. Brussels, Belgium.
-
HYDRO (2009): Seeing the Light. The use of Aluminium Support Structures in Concentrated Solar Power Energy Generating Facilities. Oslo, Norway.
-
JUNGBLUTH, N. (2007): Ecoinvent -Teil XI: Solarkollektoranlagen. Dübendorf,
Switzerland.
-
LEHMANN, H./REETZ, T./ROEWER, S./LIEDTKE, C. (2008): Ökologische Chancen und
Risiken großtechnisch angelegter solarthermischer Kraftwerke. Wuppertal, Germany.
-
VIEBAHN, P. (2004): SOKRATES-Projekt - Solarthermische Kraftwerkstechnologie für
den Schutz des Erdklimas. Stuttgart, Germany.
Parabolic troughs
The parabolic troughs which are used in most operating solar fields are silver-based mirrors
made of special flat glass (mostly with iron content) (see Figure 40). This guarantees good
reflection characteristics and a long durability.
Some companies though have fields where aluminium parabolic mirrors are tested. In comparison to glass mirrors, aluminium mirrors have the same surface reflectivity and are lighter.
While glass mirrors have an average weight of 11 kg per square meter163 aluminium troughs
have only an average weight of 7 kg per square meter which is about 35 per cent lower than
glass collectors. Especially when transportation costs are (only areas of the Sun Belt are
suitable for CSP technologies), the lower weight can play a significant role in the decision as
to which material will be used in the future.
The system frames can be made of steel and aluminium, respectively. Some companies
have developed aluminium frames which are already used in solar fields. The use of aluminium in frames for parabolic dishes varies widely because of different requirements. For the
frames of a 64 MW solar field in the USA (Nevada Solar 1) 3’402 tons of aluminium were required. The same amount was used for three 50 MW solar fields in Spain. Other requirements for aluminium frames have been found for a solar field in Florida, USA. Because of the
high possibility of hurricanes in this region, the frames must have a stronger design to with163
Data from FLABEG technical sheet of parabolic collectors.
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stand hurricane force winds. Therefore, a total of 8’165 tons of aluminium were used for this
75 MW field.
The absorber systems are made of stainless steel with selective coating. The envelopes
consist of Borosilicate anti-reflective glass. The absorber system does not use aluminium
and there is no research on using aluminium for these systems164.
Aluminium is used in parts of the power block and the cooling tower. The LCA of NEEDS
showed a total of 950 kg of Aluminium in a power block for a 50 MW solar field (Andasol I)
and a total of 624 kg for a parabolic solar field of 5 MW. The SOKRATES LCAs even showed
a total of 1’500 kg of Aluminium used in the generators (both for parabolic and Fresnel technologies). The same LCAs also showed an aluminium share of 600 kg in the cooling tower.
Particularly the cooling fins are made of aluminium.165
Figure 41: Parabolic collector at Andasol I166
The attention is on the collectors and the elevation. Other components (cooling tower, heat
pipes, generator, pre- and reheater) of solar fields only use aluminium in small amounts
where no significant potential could be identified.
Today’s minimum aluminium use (Al minimum) is given when collectors are made of glass
and the elevation is made of steel. The aluminium only exists in small amounts 0.0008
kg/kW (see Table 42). The maximum aluminium (Al maximum) amount is given when both
elevation and collectors are made of aluminium (possibility of a solar field completely processed with aluminium). Then a specific factor of 53.9 (worldwide average) kg aluminium per
kW for the elevation (truss systems) and a factor of 76.7 kg/kW for the collectors build the
basis for calculation. Summed up the result is a total specific factor of 130.6 kg aluminium
per installed kW.
For Al moderate, we assume 65.3 tons per MW (average of Al minimum and Al maximum)
of the aluminium use when solar fields are partly made of aluminium (either elevation or collectors).
164
Expert interview with Florian Höcht, Schott Solar
Expert interview with Barbara Fricke, research associate at Solarinstitut Jülich (SIJ), Germany.
166
Source: SolarMillenium.
165
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Table 42: Specific aluminium use in solar fields today [in kg/kW]
kg/kW
Collector
Al minimum
Al moderate
-
-
Al maximum
X
53.9
-
76.7
or
Elevation/Frame
Specific aluminium use in tons
per MW
-
X
0.0008
65.3
130.6
Fresnel collectors
Common like parabolic mirrors Fresnel collectors are currently made of flat-glass with a silver
mirror. Steel evaluation constructions are used to fix the (single-axis) mirrors into the sun. In
comparison with parabolic mirrors, the main advantage of these systems is their simple design that makes the components easier to produce with less material input (see Figure 42).
According to NEEDS a total amount of 285 tons of glass and 1’234 tons steel167 (and other
materials which are not important in regard of a possible substitution with aluminium) are
used for elevation and collectors by a solar field with a capacity of 5 MW168 . That implies a
specific material input per installed MW of 247 tons steel and 57 tons of glass. All in all, a 5
MW solar field uses a total of 2’209 kg aluminium in components like cooling rips of the cooling tower. In summary, aluminium currently plays a minor role for Fresnel technologies.
Figure 42: Linear Fresnel collector at test plant Almeria169
Solar towers
The aluminium use in solar towers plays a subordinate role. The heliostat mirrors (which are
composed of several small mirror modules) are made of iron and glass170. These materials
167
1’234 tons steel = 161 tons reinforcing steel + 555 tons converted steel + 519 tons rolling sheet
(calculation with precise value)
168
Viebahn (2008): p. 88.
169
Source: Fraunhofer ISE.
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guarantee good reflection characteristics and are used in all heliostat fields on the market.
The tracking systems which align the mirrors into sun beams are made of steel. The tower is
made of concrete and steel frames. Finally, the aluminium used in solar towers is in the sub
per mill range. Components which are made or partly made of aluminium are the cooling fins
of the heat exchanger (80% of the aluminium use) and electrical components (20%)171.
Figure 43: Heliostats at Solar tower Jülich172
3.5.4 Technology scenarios for Concentrated Solar Thermal Power
The various market scenarios for CSP technologies differ significantly depending, amongst
others, on the year of the studies. The lowest projected CSP capacity for 2020 is given by
the two baseline scenarios of Greenpeace (Greenpeace Energy [R]evolution baseline scenario and Greenpeace: Sauberer Strom aus den Wüsten – reference scenario) and projects
8 and 7.4 GW. The projected capacities go up to 14 till 40 GW (Viehbahn and Peter/Lehmann scenarios) (see Figure 44). Ambitious scenarios project capacities up to 84.3
GW of installed capacity of CSP technologies for 2020.
The newest report (Energy Technology perspectives) launched in July 2010 from the IEA
projects a capacity of 147 GW for 2020 which is nearly two times higher than the highest projected capacity of the other scenarios. This capacity corresponds with 1’500 newly installed
100 MW plants in the next ten years which, according to market experience, planned projects
and duration of planning, is not realistic.
For 2030 the projections of the expansion scenarios also clearly diverge. The two reference
scenarios of Greenpeace (12 and 12.8 GW) are almost under the actual planned CSP projects. A set of scenarios (Viehbahn (2008), optimistic, IEA (2010b), MEF (2010), industry, Peter/Lehmann (2007), high, Greenpeace (2008), moderate and ambitious) project an installed
capacity for CSP of 200 GW and beyond. The Greenpeace ambitious scenario and the IEA
(2010b) forecast the highest capacities of about 340 GW.
For 2050 the trends vary from 17 and 18 GW (Greenpeace baseline scenarios) to 1’524 GW
(Greenpeace (2008), ambitious). A range of scenarios lies in the middle of these projections,
170
Expert interview with Barbara Fricke, research associate at Solarinstitut Jülich (SIJ), Germany.
ibd.
172
Source: Solarturm Jülich.
171
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between 800 GW (MEF (2010), industry, Greenpeace (2008), moderate) and 1’100 (IEA
(2010b)).
In our SCENARIO BEST ESTIMATE, the capacity will rise to 30 GW in 2020 and 140 GW in
2030. The capacity of Concentrating Solar Power will be at 800 GW which is over forty times
higher than in the SCENARIO LOW (see Figure 45 and Table 43).
The SCENARIO LOW projects a capacity of 8 GW of Concentrating Solar Power technologies for 2020. For 2030 the capacity will rise to 13 GW. In 2050 the cumulated installed capacity will be at 18 GW in SCENARIO LOW.
The SCENARIO HIGH projects a capacity 85 GW for 2020, 340 GW in 2030 and 1’500 GW
for 2050. It projects a capacity that is 1’100 higher than SCENARIO BEST and 1’480 higher
than in the SCENARIO LOW.
Peter/Lehmann (2007), high
in GW
Peter/Lehmann (2007), low
1'600
MEF (2009), moderate
1'400
MEF (2009), industry
Greenpeace (2008), low
1'200
Greenpeace (2008), high
1'000
Greenpeace (2009), reference
Greenpeace (2009), moderate
'800
Greenpeace (2009), ambitious
'600
UBA (2007), projection A
UBA (2007), projection B
'400
Viehbahn (2008), very optimistic
'200
Viehbahn (2008), optimisticrealistic
Viehbahn (2008), pessimistic
'0
2010
2020
2030
2040
2050
IEA (2010b)
Figure 44: Technology scenarios for CSP technologies
Table 43: Chosen scenarios of future CSP developments in GW
in GW
today
2020
2030
2050
SCENARIO LOW
0.5
8
13
18
SCENARIO BEST ESTIMATE
0.5
30
140
800
SCENARIO HIGH
0.5
85
340
1‘500
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in GW
1'600
1'400
1'200
IFEU HIGH
1'000
IFEU BEST
ESTIMATE
'800
'600
IFEU LOW
'400
'200
'0
today
2020
2030
2040
2050
Figure 45: Scenarios for CSP technologies
To determine the electricity generation of CSP technologies and the CO2 abatement potential
of these technologies a definition of the full load hours of these technologies is required. The
problem here is that the solar radiation varies significantly in the different world regions. Additionally only some regions are suitable for use. Another problem is the storage possibility.
Depending on the future development of storage technologies the full load hours can be extended. Full load hours also depend on the different technologies themselves. Today the solar fields Andasol I+II (parabolic dishes) run with average of 3’820 full load hours173. Higher
full-load hours can be achieved with storage e.g., like in the Jordan/Aqaba Solar Water Project. But in such systems, with given solar areas, lower overall capacities can be achieved.
To avoid calculation problems it is assumed that plants only run peak load during sun radiation.
To calculate the produced electricity and later the CO2 abatement potential it is assumed that
the full load hours of today will not rise to a great extend as climatic prerequisites remain the
same. The current operating concentrating solar power plants are well suited in the Sun Belt
with full load hours of about 3’600.
173
Viebahn (2008): p. 8.
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With the assumptions of 3’600 full load hours today and in future, CSP technologies actually
generate about 2 TWhel per year. The electricity generation will rise to 29 TWh in the
SCENARIO LOW, to 108 TWh in the SCENARIO BEST ESTIMATE and to 306 TWh in the
SCENARIO HIGH in 2020. The produced electricity in 2030 will be between 47 TWh and
1’224 TWh, depending on the scenario chosen. In 2050 the electricity generation will be 65
TWh in the SCENARIO LOW about 2’880 TWh in the SCENARIO BEST ESTIMATE and
about 5’400 TWh in the SCENARIO HIGH. In comparison, global electricity generation in
2007 was 19’771 TWh.
Table 44: Generation of electricity in TWh
in TWh
2020
2030
2050
SCENARIO LOW
29
47
65
SCENARIO BEST ESTIMATE
108
504
2‘880
SCENARIO HIGH
306
1‘224
5‘400
On the basis of the yearly produced electricity of CSP technologies, CO2 abatement potential
can be calculated thus. As a result it is necessary to define a CO2 abatement factor and substitution factor. As no global substitution factor is available, we assume for a first-order estimate the same substitution factor as for PV (600 g CO2/kWh)174. Results are shown in Table
45. The CO2 abatement of CSP technologies in SCENARIO HIGH in 2050 (3’240 Mt) is
nearly as high as CO2 abatement by solar thermal collectors.
Table 45: CO2 abatement potential of CSP technologies
in Mt CO2
2020
2030
2050
SCENARIO LOW
20
30
40
SCENARIO BEST ESTIMATE
70
300
1‘730
SCENARIO HIGH
180
730
3‘240
3.5.5 Resulting current and future aluminium use in CSP
As already mentioned above, solar fields do not use aluminium for the main components of
the plants. Glass collectors are used for the collectors and steel is the main material used for
the truss systems in all CSP technologies. But there are companies which already build aluminium truss systems for solar fields. According to expert interviews, R&D trends and other
indicators there is a high potential for aluminium to not only substitute steel and glass, but to
play a significant role in future CSP technologies, especially in the collector design. Therefore, for the calculation of the overall aluminium use, assumptions have to be made with respect to the share of aluminium in the different components. The total specific aluminium use
per MW includes a fix factor of aluminium used in the components where no potential is assumed (0.0008 t/MW):
174
CO2 abatement factor for PV is set to 600 gCO2/kWh, which is slightly higher than 591 gCO2/kWh
mentioned by German Federal Ministry of Environment (FEDERAL MINISTRY OF ENVIRONMENT,
GERMANY 2009: Erneuerbare Energien in Zahlen: page 24).
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Table 46: Assumptions of the market shares of significant components of solar fields in the different
scenarios in 2020, 2030, 2050 (in %)
2020
2030
2050
Scenario
LOW
BEST
E.
HIGH
LOW
BEST
E.
HIGH
LOW
BEST
E.
HIGH
Collector
0%
10%
20%
0%
20%
50%
0%
30%
100%
Elevation
0%
40%
50%
0%
60%
70%
0%
60%
100%
0.0008
36.1
49.1
0.0008
56.8
80.6
0.0008
62.2
130.6
Total specific
aluminium use
(kg/kW)
The resulting aluminium use in the SCENARIO LOW (with the assumption of an aluminium
market share of 0% both of elevation and collectors and a low expansion scenario of CSP
technologies) is negligible. In SCENARIO BEST ESTIMATE aluminium use will be at 1.1 Mt
in 2020 with the assumption of a market share of 10% of aluminium for the collectors and
40% of the truss systems and a moderate development of CSP technologies (see Table 47).
In 2030 a market share of 20% for collectors and 60% for elevation can be assumed.
Summed up with a moderate CSP scenario, the aluminium use will be around 8 Mt. An aluminium use of about 50.8 Mt is shown until 2050 with the assumptions of a market share of
30% for collectors and 60% for elevation. If the same moderate installation rates are assumed but specific aluminium use is varied, Al maximum leads to 104’500’000 t in Scenario
Best Estimate Plus and Al minimum leads to 640 tons in Scenario Best Estimate Minus.
Significantly higher are the amounts of aluminium in SCENARIO HIGH that reflects a scenario where aluminium will be employed up to 100% in the different components. In this scenario an aluminium use of 4.2 Mt in 2020 and of 27.4 Mt in 2030 is possible. An optimal market development resulting in a market share of 100% both of collectors and truss systems
would lead to a aluminium use of as much as 196 Mt in 2050.
Table 47: Total aluminium use in CSP technologies
in t
2020
2030
2050
SCENARIO LOW
6
10
14
SCENARIO BEST ESTIMATE Minus
24
112
640
SCENARIO BEST ESTIMATE
1‘100‘000
8‘000‘000
50‘8000‘000
SCENARIO BEST ESTIMATE Plus
1'500‘000
11'300‘000
104'500‘000
SCENARIO HIGH
4‘200‘000
27‘400‘000
196‘000‘000
In SCENARIO BEST ESTIMATE an annual aluminium use of 0.3 per cent of the annual
aluminium production in the first decade between 2010 and 2020 is to be found (see Table
51). Aluminium use rises to an annual 1.9 per cent in the next decade. The years from 2031
until 2050 show a considerate share on the total production of 5.7 per cent. In SCENARIO
HIGH, the annual aluminium use in CSP technologies is at 1.2 per cent of the total production in the first decade. In the next decade between 2021 and 2030 the annual aluminium
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share on the total worldwide aluminium production rises to 6.4 per cent. With the assumptions of a total market share of 100 per cent aluminium, both in elevation and collectors, in
the year 2050, CSP technologies can reach an annual 23.1 per cent (nearly one fourth) of
the total aluminium production.
Table 48: Future total and annual aluminium use per decades in tons and as percentage of annual
global aluminium production
Annual Al use (Mt)
Annual Al use as percentage of annual Al production1
2010-2020
0.0000006
-
2021-2030
0.0000004
-
2031-2050
0.0000002
-
2010-2020
0.00000240
-
2021-2030
0.00001
-
2031-2050
0.00003
-
2010-2020
0.11
0.3
2021-2030
0.69
1.9
2031-2050
2.09
5.7
2010-2020
0.15
0.4
2021-2030
1.13
3.1
2031-2050
5.22
14.4
2010-2020
0.42
1.2
2021-2030
2.32
6.4
2031-2050
8.425
23.1
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
SCENARIO HIGH
1
Annual production: 36’400’000 tons (Source: IAI 2010).
Fresnel- and Central Receiver technologies (excursion)
Whereas parabolic troughs have been operating for over 25 years und generate electricity
under commercial circumstances, Fresnel troughs and central receivers are still in the development stage. Because data is lacking, detailed information about future aluminium use can
only be made for parabolic troughs. However, assumptions of many market actors indicate
that these technologies might have a bigger market share in future. Therefore, it is necessary
to outline a perspective on how aluminium use will change when those technologies will have
a market potential.
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The basis of the following analysis is the NEEDS LCA’s of the different technologies and focused on the fields and elevation175. Parabolic troughs, Fresnel systems and central receivers have different collector designs with a different amount of material input. Aluminium demands vary significantly for each of these technologies. For example, the amount of aluminium used to build heliostats (for central receivers) is about half the amount which is used in
the example parabolic field of the LCA. The specific aluminium use of the central receiver,
however, is one third of the one of the solar field (designed with parabolic troughs).
To compare the different technologies among each other, it is necessary to normalize the
material inputs of the different components (elevation and collector) to one MW to make precise statements. With this information, quotients can be calculated to compare Fresneltroughs and central receivers with the parabolic reference technology. Results attest to the
fact mentioned above that Fresnel troughs are much lighter than parabolic troughs. The
glass amount for collectors which is used for Fresnel technology is only 43 per cent of the
amount used for a parabolic field to get the same capacity (proportion Fresnel/parabolic of
0.43). The difference between the amounts of steel used for elevation also varies. For Fresnel troughs only around 75% of the steel amount of parabolic troughs is used.
The proportions of central receivers (in regard of parabolic troughs) go into a different direction. The amount of glass which is used for heliostats to get 1 MW capacity is 59% higher
than for parabolic troughs and the amount of steel for the elevation is 86% higher.
Table 49: Comparison of material inputs in Parabolic, Fresnel and Central receiver technologies
Name
Andasol
Novatec
SolarTres
Type
Parabolic
Fresnel
Heliostat
46 MW
5 MW
15 MW
glass
glass
glass
6’148’846
285’234
3’180’904
133’671
57’047
212’060
steel
steel
steel
15’168’192
1’234’928
9’204’250
329’743
246’986
613’617
Capacity
Collector design
Weight in kg
kg/MW
Elevation
Weight in kg
kg/MW
Proportion
Fresnel/Parabolic
Central Receiver/Parabolic
0.43
1.59
0.75
1.86
Concerning the substitution of steel and glass by aluminium, it is assumed that Fresneltroughs and heliostats materials could be replaced by aluminium as aluminium has almost
the same reflectance.
In summary, if Fresnel troughs would be the most common future CSP technology the aluminium use for CSP would decrease in a significant way because the aluminium input for collectors (25% less material demand as in parabolic trough system) and elevation (53% less
material demand) would be much less than for parabolic troughs. On the other hand, if central receivers would replace parabolic troughs in future the aluminium use would be higher
(plus 59% for collectors and 86% for elevation).
175
Viebahn (2008): p. 88.
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Aluminium use in storage systems (excursion)
The biggest problem of renewable energies now and in future will be the possibility to store
the produced energy. This is especially evident for the fluctuating energies - wind and solar
power. An additional problem is valid for CSP technologies. To use CSP for base load electricity generation it makes it necessary to store the produced electricity over the day period
when the sun does not shine. Over the whole year sun radiation is also not available every
day. Therefore, energy has to be saved (at least to balance daily fluctuations).
Possible storage systems are:





molten salt
concrete
phase Change Material storage (PCM)
pressurized Water – ruths and
hot water storage.
In regard of aluminium, Phase Change Material storage systems include aluminium. This
storage possibility has a great future potential in comparison with the other storage types176.
To store 1 MWhth (in a system of 600 MWth and a storage time of 16 h), an aluminium input
of around 3 tons is necessary.177
176
177
Compare with Viebahn (2008): 50.
Viebahn (2008): p. 87.
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3.6 Cables used in focus REn technologies: excursion
Cables are essential to transmit generated electricity from its place of generation to the place
where electricity is transformed. The requirements concerning the technical and electrical
properties of those cables can vary depending on the type of electricity generation. The distance between generation and transformation is one of the key points for the decision how to
transmit electricity. In future the need to transport electricity over long distances will increase
in a way that much effort will be necessary to overcome the associated challenges.
Large CSP power plants (like Desertec) are currently being planned or under construction in
Europe, the Middle East and in North Africa (EUMENA). In the long term the aim is to cover
big parts of the European energy demand with electricity produced in the MENA (Middle East
& North Africa). Also, offshore wind parks in the seas around Europe, especially in the North,
are under development.
Fluctuation of renewable energies, especially wind and solar energy, makes it necessary to
transport electricity over long distances to balance variations. The regional distance between
production and demand is therefore an important factor. Offshore wind energy is available in
the seas of Northern and Western Europe. Concentrating solar power can only be produced
in the Mediterranean regions of Southern Europe.
Additionally, offshore wind energy needs to improved technology to transport electricity over
long distances. The existing European grid system is unsuitable for these challenges.. AC
cables have high transmission losses so that they are unsuitable for high distances. Another
reason why electricity transportation over long distances will get more important is that the
centers (conurbations; big cities) where most of the electricity is needed are not suitable to
produce energy in vast amounts.
HVDC (High Voltage Direct Current) cables are used currently as they are the best option to
transport electricity over long distances without high performance losses (approx. 10 per cent
at a distance of 3’000 km). HVDC are cables with a voltage of over 100 kV. Currently used
cables for energy transportation are cables with about 800 kV which can transport an electric
load of 10 GW over distances of about 3’000 km178.
In comparison to conventional AC high voltage lines HVDC need an AC/DC converter instead of a common transformer to change the AC voltage into DC. This makes HVDC lines
very expensive so they are not economically beneficial until a distance of about 600 kilometers for overhead lines and about 50 kilometers for submarine cables179.
Currently, a total of about 75,000 MW (divided into 92 different projects) are transmitted
through HVDC lines all over the world180. The overwhelming majority of these cables have
voltages between 100 kV and 500 kV. The current stage of market and future development
assume a wide range future distribution of 800 kV HVDC lines.
178
Viebahn (2008): p. 87.
ABB (2010).
180
May (2005): p. 31.
179
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Figure 46: HVDC cables (submarine in front; overhead in back)181
To make future assumptions of the potential of aluminium use for HVDC lines, a line with a
voltage of 800 kV has been analyzed. Overhead cables and submarine cables use different
materials because of special requirements they need to fulfill. While both cables have to resist corrosion, overhead lines must to be resistant against air impacts or desert influences
like sand storms and submarine cables must to be resistant against water and the influences
of salt water. Thus the structure of the cables more specifically the coat has to be different.
The main material used for overhead cables is reinforcing steel with 150 tons used for a one
kilometer long cable. Chromium steel has an amount of 12.8 tons per kilometer. Aluminium is
the second most important material in HVDC overhead cables with a total amount of 34.8
tons. Other materials are concrete and ceramic tiles with a total amount of 4.2 tons182. Submarine cables have a completely different structure and use different materials. The main
materials are chromium steel, copper and lead. Differing figures for aluminium use in submarine cables are shown in Table 50.
Table 50: Specific aluminium use for HVDC cables
Material
Unit
Material unit/km
Material unit/km
HVDC Overhead
HVDC Submarine
Reinforcing steel
kg
150‘000
-
Concrete
m3
163
-
Aluminium
kg
34‘800
1/1‘100/2‘200183
Ceramic tiles
kg
4‘000
-
Chromium steel
kg
12‘800
192’000
Copper
kg
-
152’000
Lead
kg
-
136’000
Paper
kg
-
48’000
Polybutadiene
kg
-
8’000
181
Source: ABB.
May (2005): p. 110.
183
Source: Prysmian Cables and Systems (2010), own assumptions.
182
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kg
-
18’400
Potential of aluminium use in HVDC cables in future
The aluminium use for one kilometer of overhead cable is around 35 tons. Projected to a cable transmission line with a distance of 3’000 kilometers, the total amount of aluminium for
one EU-MENA electricity transmission line is 105’000 tons.
With regard to the future installed capacity for wind and CSP approximately 10 of those
transmission systems, with an average length of 3’000 kilometers, could be installed in the
next 40 years in the EU-MENA region (see Figure 46)184. This would correspond to a total
aluminium use, for HVDC overhead cables, of approximately 1’050’000 tons (approx. 1 Mt).
Assuming an additional 1’100 kilometers of submarine cables will be installed among Mediterranean neighboring countries185, aluminium sales for HVDC submarine cables that connect Europe and Africa (e.g. DESERTEC) could be 1.1 tons if only marginal amounts of aluminium are used. (e.g. aluminium foil), 1’210 tons if moderate amounts of aluminium are
used (e.g. aluminium water barrier) or 2’420 tons if the maximum amount of aluminium is
used (e.g. strengthened aluminium water barrier).
Figure 47: Trans-Mediterranean Interconnection for Concentrating Solar Power186
184
Own assumptions.
Trieb (2006): page15; own assumptions.
186
Source: DLR.
185
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4 Overall potential of aluminium
4.1 Summary of specific aluminium use in renewable energy systems
Solar thermal collectors
Currently it is estimated that 0.3 Mt of aluminium are used in solar thermal collectors, mainly
in absorbers, casings and frames. Studies support the trend of increasing aluminium use in
absorbers. Out of 289 systems analyzed, 34% use aluminium absorbers with increasing tendency. In evacuated tube solar thermal collector frames, steel could be replaced by aluminium. While both aluminium and steel are readily available in local markets, aluminium has a
distinctive advantage as it is lighter than steel.
Systems with water tanks are very common in China and developing countries. They are
primarily made of steel to prevent corrosion and because of the lower prices. In water tanks,
stainless steel can be replaced by aluminium, but it is recommended to only replace steel in
the outer tank as the inner tank is permanently in contact with water. If a reflector shield is
used, it could be made of aluminium due to its good reflectance characteristics. A reflector
shield enhances energy yield of absorbers significantly, therefore, a very high market potential for aluminium can be found. If this substitution potential was realized, the specific use of
aluminium could be increased from 3.1 kg/m² to 4.3 kg/m² (flat-plate) or 0.9 kg/m² to 4.3
kg/m² (evacuated tube).
Wind turbines
The material predominantly used in wind turbines is steel which accounts for about 85% of
the total material input, with aluminium only playing a subordinate role. It is estimated that
around 0.1 Mt of aluminium are processed in wind turbines today, primarily in nacelles and
rotors.
While material usage is and will continue to be dominated by steel, the wind turbine nacelle
and rotor casings are potential components where aluminium use could be increased.
Photovoltaic systems
Aluminium in PV systems is used predominantly in construction/mounting structures (72% of
total aluminium input), followed panel frames (22%), and lastly inverters (6%). Our review
shows that between 23 kg/kW and 59 kg/kW of aluminium are used. The advantage of aluminium is that it is lighter than other metals, which is very important for construction/mounting
structures. Profiles for mounting are primarily made of aluminium due to its lighter weight.
Furthermore aluminium is recyclable and makes it easier for profile geometries to meet system requirements.
The full market sales potential of aluminium in photovoltaic systems would unfold if aluminium were used more often for mounting and frames. There is no clear trend that might indicate an increase or decrease of aluminium use for PV technologies. But market development
for panels without frames and wooden frames as well as developments in mounting materials
should be looked at closely in future.
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Solar cookers
Usage of aluminium in solar parabolic cookers varies widely. Solar parabolic cookers consist
of a frame and a reflector. Either no aluminium is used at all (e.g. reflector made of optical
polyester and/or wooden frame) or all components are made of aluminium. Usage varies
widely between 0.1 kg/unit if no aluminium is used (e.g. reflector made of optical polyester
and/or wooden frame) and 20 kg/unit if both components are made of aluminium. Solar
community kitchen reflectors are usually made of steel and reflecting glass. For the mounting
structure steel is used intensively while aluminium is found in the profiles which bear the reflectors.
Even if aluminium use potential is low, when compared to other technologies, solar cookers
could be a favourable technology on which to focus, especially with regard to CDM projects.
Since there is no clear trend in which direction material inputs will evolve for solar cookers,
cheap and light systems which don’t currently use aluminium should be further observed in
the upcoming years.
CSP
Concentrated solar power (CSP) based on parabolic troughs are silver-based mirrors made
of special flat glass. The system frames can be made of steel and aluminium, respectively.
Some companies have developed aluminium frames which are already used in solar fields.
The use of aluminium for parabolic troughs varies widely because of different build requirements (e.g. to withstand storms). The absorber systems are made of stainless steel with selective coatings and the envelopes consist of Borosilicate anti-reflective glass. Aluminium is
used in parts of the power block and the cooling tower. Specifically the cooling fins are made
of aluminium.
Minimum aluminium use is given when collectors are made of glass and the elevation is
made of steel. The maximum aluminium amount is given when both elevation and collectors
are made of aluminium. In that case the specific aluminium use could increase to 131 kg/kW
in an optimistic scenario.
If Fresnel troughs were the most common future CSP technology, the aluminium use for CSP
would decrease significantly compared to parabolic troughs because the aluminium input for
collectors and elevation would be much less than for parabolic troughs. On the other hand, if
central receivers would replace parabolic troughs as alternative CSP technology the aluminium use would be higher.
All technologies
Comparing the aluminium use of the various technologies, Figure 48 demonstrates that particularly PV and CSP have high specific amounts of aluminium in Al moderate, and even
more in Al maximum scenario. This is due to a rather high percentage of aluminium in the
components as well as (e. g. compared to solar collectors) rather low conversion efficiencies.
If aluminium use moved from Al moderate to Al maximum, especially in PV and CSP systems, total as well as annual aluminium sales could be maximized substantially. Possible future trends and maximization options of aluminium use are summarized in Table 51. It must
be noted that in Figure 48, the use is normalized to a kW heat for collectors or electricity for
the other technologies.
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Specific aluminium use (kg/kW)
140
120
100
80
Al maximum
60
Al moderate
Al minimum
40
20
0
Solar
Solar
Wind
Wind
collector collector Onshore Offshore
FP
ET
PV
CSP
Figure 48: Specific aluminium use in the various technologies (per kW heat (solar thermal collectors)
or kW electricity (others); FP: flat-plate, ET: Evacuated tube)
Table 51: Summary of future trends regarding specific aluminium use in renewable energy systems
Component
Solar
thermal
collectors

Flat-plate
Evacuated
tube

market is dominated by copper, but increase in
aluminium use in recent years
aluminium needs to be thicker than copper to
have same conductivity
Frame


steel replacement possible
advantage of aluminium as it is lighter
Reflector shield


high market potential
aluminium increases absorber efficiency

copper replacement possible, but low replacement potential

if water storage tanks are used, replacement of
steel at least in outer tank is possible

aluminium in covering of nacelle possible (e.g.
Enercon turbine)
no significant difference between on- and offshore wind turbine replacement potential
cast iron and glass fibres could be replaced
increased use of light weight composites
Absorber
Header pipes
&Heat pipes
Water tanks
Wind
turbines
Nacelle
Rotor
PV
Remarks
-
Frame





profiles and frames are mostly made of aluminium
advantage of aluminium: combination of stiffness
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and light weight characteristics
Mounting
Solar
cookers
CSP


no clear trend
developments in frame and mounting materials
should be closely monitored

either solar cooker consists of 100% aluminium
or not at all
developments concerning cheap and light systems not using aluminium should be monitored
carefully
huge potential if elevation and collectors are
made of aluminium instead of glass and steel
aluminium used in components like cooling rips
of the cooling
replacement potential in troughs where aluminium replaces steel

Parabolic
troughs
Elevation &
Collector


Fresnel

4.2 Overall use of aluminium in renewable energy systems
To calculate the overall market sales potential of aluminium in renewable energy systems the
specific aluminium use as shown above was linked to the various technologies installation
scenarios.
We define three scenarios and two variations (sub-scenarios): In SCENARIO BEST
ESTIMATE, the specific aluminium use and technology scenario are based on moderate assumptions. As this scenario is the most likely reference scenario, it is further differentiated by
assuming moderate installation rates and maximum specific aluminium use (SCENARIO
BEST ESTIMATE Plus) as well as moderate installation rates and minimum specific aluminium use (SCENARIO BEST ESTIMATE Minus). A pessimistic estimate regarding the specific
aluminium use and the expansion of renewable energy systems constitutes SCENARIO
LOW, while the optimistic SCENARIO HIGH assumes a high specific aluminium use and optimistic rates of expansion. The two latter scenarios, however, are to be interpreted as the
upper and the lower end of the scenario funnel and are not considered to be very likely.
In 2020, total aluminium use for all renewable energy systems would be around 6 Mt in
SCENARIO BEST ESTIMATE (see Figure 49 and Table 53), increasing to 20 Mt in 2030 and
88 Mt in 2050. If moderate installations were assumed and moderate use of aluminium was
optimized from Al moderate to Al maximum (SCENARIO BEST ESTIMNATE Plus), market
sales could reach 188 Mt in 2050.
If aluminium market sales potential and rates of installations are assumed to be pessimistic,
significantly lower amounts of 4 Mt are projected for the SCENARIO LOW in 2050, whereas
in the SCENARIO HIGH 470 Mt are projected for the year 2050 if installed capacities develop optimistically and aluminium replacement potential is fully tapped (very optimistic assumptions).
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Mt Aluminium
500
SCENARIO HIGH
400
SCENARIO BEST
ESTIMATE Plus
300
SCENARIO BEST
ESTIMATE
200
SCENARIO BEST
ESTIMATE Minus
100
SCENARIO LOW
0
2020
2030
2040
2050
Figure 49: Total aluminium invested in renewable energy systems in the different scenarios
In Figure 50 annual aluminium sales in renewable energy systems are shown for the
SCENARIO BEST ESTIMATE, in which the total annual aluminium use increases steadily.
From today until the year 2020, approximately 0.5 Mt or 1.4 percent of annual aluminium
production would be used in renewable energy systems every year. Between 2021 until
2030, total annual aluminium use for renewable energy systems will increase to around 1.5
Mt or four percent of annual aluminium production and from 2031 until 2050 to 3.3 Mt or
nearly 9 percent of annual aluminium production187.
It is clear that solar-based technologies (CSP, PV and solar thermal collectors) are most significant to the overall potential. Concerning solar cookers only an overall potential until 2050
has been estimated due to a lack of scenario information. Until 2050 approximately 0.3 Mt
would be processed, meaning that annual aluminium use is low (less than 0.1% of annual
aluminium production).
187
IAI Statistics (2010).
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Mt/a
% of annual
aluminium production
9,0
8,0
20
7,0
6,0
15
5,0
4,0
Wind turbines
10
Photovoltaic
systems
5
CSP
3,0
2,0
Solar thermal
collectors
1,0
0,0
0
today-2020
2021-2030
2031-2050
Figure 50: Projected annual aluminium use in renewable energy systems in the SCENARIO BEST
ESTIMATE188
In Figure 51 and Figure 52 annual aluminium sales for the two variations (sub-scenarios),
which assume the same moderate installation rates as in SCENARIO BEST ESTIMATE with
a shift from Al moderate to Al maximum, are indicated. As shown in SCENARIO BEST
ESTIMATE Plus, the rise of aluminium use from Al moderate to Al maximum in solar-driven
technologies seems to be very promising. Here, aluminium sales could be more than doubled in CSP and solar thermal collectors and could be almost tripled in PV technologies.
Mt/a
% of annual
aluminium production
9,0
8,0
7,0
20
Solar thermal
collectors
15
Wind turbines
10
Photovoltaic
systems
6,0
5,0
4,0
3,0
2,0
5
CSP
1,0
0,0
0
today-2020
2021-2030
2031-2050
Figure 51: Projected annual aluminium use in renewable energy systems in the SCENARIO BEST
ESTIMATE Plus
188
Due to very low figures solar cookers have been exempted.
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If aluminium use decreased from Al moderate to Al minimum as assumed in SCENARIO
BEST ESTIMATE Minus, only PV systems would show a noteworthy aluminium market sales
potential.
% of annual
aluminium production
Mt/a
9,0
8,0
7,0
20
Solar thermal
collectors
15
Wind turbines
6,0
5,0
4,0
10
Photovoltaic
systems
3,0
2,0
5
1,0
CSP
0,0
0
today-2020
2021-2030
2031-2050
Figure 52: Projected annual aluminium use in renewable energy systems in the SCENARIO BEST
ESTIMATE Minus
Figure 53 and Figure 54 show results for SCENARIO HIGH and SCENARIO LOW. As mentioned earlier, these scenarios are to be interpreted as the upper and the lower end of the
scenario funnel and are not to be considered very likely.
% of annual
aluminium production
Mt/a
9,0
8,0
20
7,0
6,0
15
5,0
4,0
Wind turbines
10
Photovoltaic
systems
5
CSP
3,0
2,0
Solar thermal
collectors
1,0
0,0
0
today-2020
2021-2030
2031-2050
Figure 53: Projected annual aluminium use in renewable energy systems in the SCENARIO HIGH
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% of annual
aluminium production
Mt/a
9,0
8,0
7,0
20
Solar thermal
collectors
15
Wind turbines
6,0
5,0
4,0
10
3,0
2,0
Photovoltaic
systems
5
CSP
1,0
0,0
0
today-2020
2021-2030
2031-2050
Figure 54: Projected annual aluminium use in renewable energy systems in the SCENARIO LOW
With the projected market expansion of renewable energy systems, considerable amounts of
electricity and heat can be generated. For example, in the SCENARIO BEST ESTIMATE total electricity produced in 2050 is projected to supply 50% of current global electricity. Other
renewable energy sources such as hydropower, biomass and geothermal will complement
this generation. In SCENARIO LOW and HIGH these shares are 20% and are around 100%
of 2008 electricity consumption. Taking into consideration the rising electricity demand and
the generation of electricity in other renewable electricity systems, the latter scenario would
imply a move toward a 100% renewable electricity system and thus represents the upper
boundary of a probable development. Please note that the focus of this calculation is to determine aluminium market sales potentials for individual technologies and not the creation of
a synchronized set of global energy scenarios.
Correspondingly, in 2020 renewable energy systems in SCENARIO BEST ESTIMATE would
help abate 1’300 Mt of CO2 emissions compared to marginal technologies (gas and coal
electricity generation and gas/oil heating systems) (see Figure 55 and Table 55 for more details). In comparison, the annual emitted CO2 emissions in 2007 was 28’962 Mt of CO2. In
2030 3’200 Mt of CO2 would be abated and in 2050 7’300 Mt would be saved with renewable
energy systems. Complemented by other renewable technologies and efficiency measures,
significant carbon savings could be achieved when compared to the current levels. Projections in the two other scenarios vary from 1’800 Mt (SCENARIO LOW) to 18’200 Mt
(SCENARIO HIGH) for 2050.
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Mt CO2/a
250
Solar thermal
collectors
200
Wind turbines
150
PV
100
Solar cookers
50
CSP
0
today-2020
2021-2030
2031-2050
Figure 55: Projected CO2 abatement potential in SCENARIO BEST ESTIMATE compared to marginal
technologies (gas and coal electricity generation and gas/oil heating systems)
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SEIFERT, D. (1999): Proposals for a Global Solar Cooker Program. - , Germany.
SOLAR ENERGY INDUSTRIES ASSOCIATION (2009): US Solar Industry Year in Review 2008.
Washington D.C., USA.
TANGLER, J. L. (2001): The Evolution of Rotor and Blade Design. Palm Springs, USA.
TRIEB, F. (2006): Trans-Mediterranean Interconnection for Concentrating Solar Power. Stuttgart, Germany.
TYROLLER, M. (2004): Solarsterilisator für Entwicklungsländer. -/-.
UMWELTBUNDESAMT (2007): Zukunftsmarkt solarthermische Stromerzeugung. Dessau, Germany.
US DEPARTMENT OF ENERGY (2001): Wind Turbine - Materials and Manufacturing fact sheet.
Washington D. C., USA.
VESTAS (2006a): Life cycle assessment of electricity produced from onshore sited wind power
plants based on Vestas V82-1.65 MW turbines. Randers, Denmark.
VESTAS (2006b): Life cycle assessment of offshore and onshore wind power plants based on
Vestas V90-3 MW turbines. Randers, Denmark.
VIEBAHN, P. (2004): SOKRATES-Projekt - Solarthermische Kraftwerkstechnologie für den
Schutz des Erdklimas. Stuttgart, Germany.
VIEBAHN, P. (2008): NEEDS - Final report on technical data, costs, and life cycle inventories
of solar thermal power plants. Stuttgart, Germany.
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WEIß, W. /BERGMANN, I./STELZER, G. (2009): Solar Heat Worldwide: Markets and contribution
to the energy supply 2007. Gleisdorf, Austria.
WORLD ECONOMIC FORUM (ed.) (2009): Task Force on Low-Carbon Prosperity: Recommendations October 2009. Geneva, Switzerland.
XIAOFU, C. / TINGCUN, H. (2009): Development and Application of Solar Cooker in China, International Solar Food Processing Conference 2009. Indore, India.
Interviews conducted
Interview with Mr Glombitza, Key Account Manager Deutschland, Greenonetec, 15 June
2010.
Interview with Ms Qiu, Sales manager, Hejiasun, 11 June 2010.
Interview with Mr Horace, Trade Department, Sangle Solar, 11 June 2010.
Interview with Mr Xu, Sales Manager, Sidite Solar Water Heater, 11 June 2010 at Intersolar
Fair Munich.
Interview with Mr Vasiliadis, Export Department, Nobel Solar Innovations, 11 June 2010.
Interview with Mr Kohlenbein, Sales, Greenonetec, 14 June 2010.
Interview with Mr Höhl, Nordex area manager South Germany, 13 June 2010.
Interview with Mr Heim, Mounting Sytems, 7 July 2010.
Interview with Mr. Grützner, Schletter, 12 July 2010.
Interview with Mr Michelbauer, EG Solar, 21 June 2010.
Interview with Ms Feldmann, HERA - Poverty-oriented basic energy services, GTZ, 16 March
2010.
Interview with Mr Veit, EG Solar at Intersolar, 12 June 2010
Interview with Mr Seifert, EG Solar, 2 July 2010.
Interview with Ms Hoedt, assistant of Wolfgang Scheffler, 1 July 2010.
Interview with Mr Veit, EG Solar at Intersolar, 12 June 2010.
Interview with Florian Höcht, Schott Solar.
Interview with Mr Basilhet, idCook, at Intersolar, 12 June 2010
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Aluminium and Renewable Energy Systems
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Interview with Mr. Dasbach from Almeco-Tinox GmbH, 28 June 2010.
Interview with Mr Cabarrubia, director of production, Soltop Schuppisser AG, 29 April 2010.
Interview with Mr Hoffmann, Jenni Energietechnik, 6 July 2010.
Interview with Bernd Sitzmann, Consolar AG, 13. July 2010.
Interview with Mr Thole, Schüco International, in February 2010.
Interview with Mr Roinson, Apricus Solar, 11 June 2010.
Interview with Barbara Fricke, research associate at Solarinstitut Jülich (SIJ), Germany.
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6 Annex
6.1 Detailed results
Table 52: Projected annual aluminium use for all Renewable Energy Systems (million tons, Mt)
Annual Al use
in Mt
Annual Al use as percentage of annual Al production189 (rounded)
2010-2020
0.05
0.12
2021-2030
0.13
0.33
2031-2050
0.08
0.21
2010-2020
0.17
0.5
2021-2030
0.39
1.1
2031-2050
0.59
1.6
2010-2020
0.51
1.4
2021-2030
1.45
4.0
2031-2050
3.31
9.1
2010-2020
1.11
3.1
2021-2030
3.40
9.3
2031-2050
8.76
24.1
2010-2020
3.70
10.2
2021-2030
10.24
28.1
2031-2050
16.26
44.7
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
SCENARIO HIGH
189
Aluminium production: 36.4 million tons.
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Table 53: Projected total aluminium use (million tons, Mt)
2020
2030
2050
0.04
0.08
0.14
0.1
1.8
4.32
15.2
0.26
4.7
11.19
30.4
0.93
16.5
39.34
69.2
0.03
0.05
0.07
0.04
0.21
1.97
0.12
0.52
3.66
0.27
1.16
7.38
3.88
8.70
12.92
1
2
3
5
16
2
5
7
13
75
4
14
19
35
189
-
-
0.000001
-
-
-
-
0.0083
0.25
1.66
3.34
0.000006
0.000024
1.1
1.5
4.2
0.00001
0.00011
8
11.3
27.4
0.00001
0.00064
50.8
105
196
SCENARIO LOW
1
2
4
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
SCENARIO HIGH
2
6
13
39
5
20
39
142
15
88
188
470
in million tons (Mt)
Solar thermal
SCENARIO LOW
collectors
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
SCENARIO HIGH
Wind
SCENARIO LOW
turbines
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
SCENARIO HIGH
PV
Solar
cookers190
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
SCENARIO HIGH
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
SCENARIO HIGH
CSP
TOTAL
(rounded)
190
SCENARIO LOW
SCENARIO BEST ESTIMATE Minus
SCENARIO BEST ESTIMATE
SCENARIO BEST ESTIMATE Plus
SCENARIO HIGH
An overall potential is indicated because no scenario exists.
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Table 54: Projected electricity and heat generation of the selected systems in 2020, 2030, 2050 in
TWh
in TWh
HEAT
TWhthermal
Solar thermal
collectors
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
2020
300
700
2‘600
Wind
turbines
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
820
1‘310
2‘550
1‘230
2‘790
6‘640
1‘640
6‘240
10‘920
PV
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
35
90
280
100
260
1‘470
190
720
3‘880
CSP
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
29
108
306
47
504
1‘224
65
2‘880
5‘400
Total
(rounded)
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
880
1‘510
3‘140
1380
3‘550
9‘330
1‘900
9‘840
20‘200
Electricity
TWhel.
109
2030
540
1,900
5‘100
2050
1‘000
6‘600
11‘600
Aluminium and Renewable Energy Systems
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Table 55: Projected CO2 abatement potential of renewable energy systems in million tons (Mt) compared to marginal technologies (gas and coal electricity generation and gas/oil heating systems)
2020
2030
2050
SCENARIO LOW
90
160
310
SCENARIO BEST ESTIMATE
SCENARIO HIGH
220
800
560
1‘500
2,000
3‘500
Wind turbines
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
600
1’000
2’000
1‘000
2’200
5’200
1’300
4’900
8’500
PV
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
21
55
170
60
156
880
100
430
2‘300
SCENARIO LOW
-
-
8
SCENARIO BEST ESTIMATE
SCENARIO HIGH
-
-
208
618
SCENARIO LOW
SCENARIO BEST ESTIMATE
SCENARIO HIGH
20
70
180
30
300
730
40
1‘730
3‘240
SCENARIO LOW
700
1‘300
1‘800
1‘300
3‘200
3‘200
8‘300
9‘300
18‘200
in million tons (Mt)
Solar thermal
collectors
Solar
cookers191
CSP
TOTAL
(rounded)
SCENARIO BEST ESTIMATE
SCENARIO HIGH
191
An overall potential is indicated because no scenario exists.
110