2021 International Conference on Electrical, Computer, Communications and Mechatronics Engineering (ICECCME) | 978-1-6654-1262-9/21/$31.00 ©2021 IEEE | DOI: 10.1109/ICECCME52200.2021.9591148
Proc. of the International Conference on Electrical, Computer, Communications and Mechatronics Engineering (ICECCME)
7-8 October 2021, Mauritius
A Comparative Study of the Energy and
Environmental Performance of Cement Industries in
Ethiopia and Sweden
Alebachew T. Mossie,
School of Electrical and
Computer Engineering,
Addis Ababa University
Addis Ababa, Ethiopia
mossie@kth.se
Micheal G. Wolde
School of Mechnical and
Industrial Engineering,
Addis Ababa University
Addis Ababa, Ethiopia
mwolde@kth.se
Getachew B. Beyene
School of Electrical and
Computer Engineering,
Addis Ababa University
Addis Ababa, Ethiopia
getachewb@gmail.com
Abstract – Cement industry is both energy and emission
intensive. This paper examines energy and environmental
performance of cement plants in Ethiopia and Sweden. Energy
intensity (thermal and electrical), alternative fuel (AF) share, CO2
emission intensity and clinker substitute rate are applied to
compare Ethiopia and Sweden cement industries. In most of the
parameters, the Ethiopian cement industry ranks lower than the
Sweden cement industry. The average thermal and electrical
energy intensities for the Ethiopian cement industry is 3.76
gigajoules per tonne of clinker (GJ/t clinker) and 138.6 kilowatt
hours per tonne of cement (KWh/t cement), respectively. Whereas,
in Sweden cement industry, the average intensity is about 3.6 GJ/t
clinker for thermal and 131 KWh/t cement for electricity. The
emission intensity is 0.853 tonne CO2 /tonne clinker (0.853t CO2/t
clinker) in Ethiopia and 0.701t CO2/t clinker in Sweden. The
alternative fuel (AF) share reaches 62% in Sweden cement
industry, while in Ethiopia the share is almost insignificant (less
than 1%). Adoption of specific energy efficiency measures, such as
waste heat recovery power plant (WHRPP) and thermal fuel
switch, significantly improved both the energy and environmental
performances of Sweden cement industry. Therefore, this study
suggests deployment of WHRPP and raise of AF share in
Ethiopian cement industry, but the technical and economic
viability of these measures should be investigated in the context of
Ethiopian cement plants.
Keywords – energy intensity, CO2 emission intensity, alternative
fuel, energy efficiency measures
I.
INTRODUCTION
Cement production is continuously increasing as a
consequence of new resident and infrastructure needs to satisfy
global population [1]. The annual global cement production is
forecasted to grow by 12-23% in 2050 [2]. According to
International Energy Agency (IEA), the annual global
production reached a high of 4100 million tonnes (Mt) of
cement in 2019; China and India being the leading countries
accounting for some 55 % and 8% of the global production,
respectively [3]. Production is likely to decline in China while
increases are projected in developing regions like Africa and
Asia [2]. In 2019, East Africa cement market reached a volume
Björn Palm
Dilip Khatiwada
Department of Energy
Department of Energy
Technology, KTH, Royal
Technology, KTH, Royal
Institute of Technogy
Institute of Technology
Stockholm, Sweden
Stockholm, Sweden
Björn.Palm@energy.kth.se Dilip.khatiwada@energy.kth.se
of 35.5Mt, Ethiopia has the largest market share with an
installed production capacity of 16.5Mt [4, 5].
The cement manufacturing sector is third largest industrial
energy consumer and major contributor to climate change;
accounting for about 7% (10.7 Exajoules) and 8% of the global
industrial energy use and CO2 emission, respectively [2, 6, 7].
A typical cement plant using the modern dry process kiln
technology consumes a primary energy of about 75% fossil fuel
and 25% electrical energy. The fossil fuel is used to generate
process heat required for pyro-processing (clinker production
process) in a kiln. In a modern cement plant, the specific
thermal energy consumption varies between 2.9 to 4.18 GJ/t
clinker depending on the technological stack i.e. the
combination of the staged pre-heaters and pre-calciner, and
clinker cooler [8]. The specific electrical energy consumption
is about 110 KWh/t cement, roughly two-thirds of this energy
is used for raw material and cement grinding process [9, 10].
IEA’s sustainable development scenario (SDS) recommends,
global average thermal and electrical intensity to be 3.1 GJ/t
clinker and 85 kWh/t cement by 2030, respectively [6].
Similarly, the direct CO2 intensity of cement production shall
be 0.48t CO2/t cement by 2030. Energy efficiency improvement
(EEI), uptake of alternative fuel, use of blended cement and/or
clinker substitutes, and deployment of carbon capture storage
(CCS) technologies are identified as the main levers for the
reduction of CO2 in the SDS [2].
In Sub-Saharan Africa, energy intensity of cement
production is in the range of 3.35 - 4.19 GJ/t clinker for thermal
and 105 - 140 kWh/t cement for electrical. Sub-Saharan Africa
cement is relatively energy intensive as compared to global
energy performance record, for instance in India/Europe the
average energy intensity is about 3.14/3.67 GJ/t clinker for
thermal and 85/111 kWh/t cement for electrical [11, 12].
Ethiopia cement industry, which is part of Sub-Saharan Africa
cement, has 15 large and medium sized operational cement
plants [5]. Monitoring energy performance and related CO2
intensity of a cement plant is a first step in understanding the
potential for improvement. With this in mind, this study first
examined the overall energy performance and related CO2
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intensity of cement plants in Ethiopia and Sweden. Then, key
performance parameters are used to compare. The comparison
is used to understand the potential gaps in Ethiopian cement
sector.
II.
METHODS AND DATA SOURCE
Literature review, interviews, data collection through visits,
and consultation with experts working in the industries are the
methods employed to complete this study. The required data are
collected from Cementa, the only cement producer in Sweden.
In Ethiopia, the data is collected from six of the largest cement
plants (LCP) that covers nearly 78 % of the country’s installed
production capacity. The data is processed to obtain key
performance parameters such as specific energy consumption,
share of alternative fuel, and clinker substitution.
The paper begins with a brief presentation of Ethiopian and
Sweden cement industries. Then, presents the energy and
environmental performance of the industries in both countries.
Finally it provides discussion and analysis, comparison and
concluding remarks.
III.
OVERVIEW OF ETHIOPIAN CEMENT INDUSTRY
Cement industry is one of the oldest and rapidly developing
sector in Ethiopia. Ethiopia has an abundant reserve of
limestone, clay, silica, sand, gypsum and pumice [13]. Portland
Pozzolanic Cement (PPC), Ordinary Portland Cement, and
Portland Limestone Cement are common types of products with
a production share of about 81.1%, 18% and 0.9%, respectively.
The LCP are built upon the modern dry process kiln technology
(multistage pre-heaters and a pre-calciner), whereas medium
sized plants utilize the oldest vertical shaft kiln technology
(VSK). The LCP adopted their technology from Europe
(Germany and Denmark) and medium sized plants use the
Chinese VSK technology.
intensive than HFO. However, significant change in emission
was not reported after the switch. The energy cost which was
50 - 60% before the switch was reduced to 40 - 45%, this energy
cost is not within the acceptable global standard (20 - 40%) [15,
16, 17]. Fig. 1 shows the thermal fuel consumption trend in the
LCP, 2013 - 2018. In the second step, it was planned to
substitute 40% of the thermal fuel by biomass (or alternative
fuel, [AF]) by 2020 [17]. In this regard, agricultural residue
(sesame and rice husks) was used as thermal energy carrier in
two of the LCP kiln, namely, Mossobo and National cement
factories. Most recently, Dangote, newly emerged LCP,
successfully co-processed scraped tyre and polypropylene bag.
The same plant is under discussion with CCIIDI to utilize
600,000 tons of banned local transformers PCB
(polychlorinated biphnile). Nevertheless, the share of AF is
insignificant in the sector (See Fig. 2)
According to [18], the use of AF sources (such as scraped
tyre, refuse derived fuel [RDF] from municipal solid waste,
agricultural residue/biomass and other industrial wastes) in
Ethiopian cement firms is at infant stage. The study [18]
indicated that RDF, scraped tyre and biomass represent 35
million GJ/year of thermal energy. In another study [15], the
potential of agricultural residues (like Coffee husk, Sesame
husk, Cotton Stalk, Saw dust) and MSW as thermal energy
carrier is estimated to be 3.6Mt of clinker/5.4Mt of cement per
year.
In terms of electrical energy, all cement plants are
dependent on the national electricity grid (mainly, hydropower
generated), which is under immense stress due to inefficient
power grid infrastructure and supply shortage [19, 20]. Current
reports show that frequent power interruption is hampering the
sector’s productivity seriously.
Large share of imported thermal energy carriers, i.e. coal,
heavy furnace oil (HFO), pet coke, and gasoil, are used in the
production of clinker. Due to the large share of fossil fuel, the
sector is highly emission intensive, for example, the direct CO2
emission significantly increased from 2.6 Mt in 2013 to 6.3 Mt
in 2018 [14]. Fig. 1 shows the CO2 emission trend in Ethiopian
cement industry. Since the industry is highly dependent on
imported fossil fuel, energy cost accounts for major portion of
the overall operational expense. To mitigate the high energy
cost characteristics and corresponding CO2 intensity, a two-step
energy efficiency (EE) programme, namely Thermal-FuelSwitch, have been lunched, with the assistance of Chemical and
Construction Inputs Industry Development Institute (CCIIDI).
CCIIDI is a responsible government stakeholder that provides
assistance for the sustainable development of the sector,
particularly, for achieving CO2 emission reduction target set in
Ethiopia’s Climate Resilient Green Economy Strategy [8].
Within this strategy, Ethiopia recognized climate change and
has committed itself to a low carbon development path.
In the first step of the EE programme, thermal fuel is
switched from HFO to coal, since coal is slightly less emission
.
Fig. 1, 2 & 3. CO2 emission trend, Thermal fuel consumption, and Share
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IV.
OVERVIEW OF SWEDISH CEMENT INDUSTRY
Cementa, under HeidelbergCement Group, has two plants
located at Slite (island of the southeast coast) and Skövde in
southern Sweden. In 2020, the company produced 2.7 million
tons of cement. The plant located at Slite is the largest plant,
with two modern rotary kilns (6 stage pre-heater and precalciner) and has a total production capacity of 300 t/h. The
production is mainly driven by fossil fuels such as coal and pet
coke, AF, and electrical energy. [22]
In Cementa, the term “AF” represents biomass and different
forms of waste such as scraped car tires, municipal solid waste,
meat production residues, woody biomass, sewage sludge,
textiles, and paper and agricultural residues. AF dominated the
fuel mix, the substitution rate reached a maximum of 62% in
2020 (see Fig. 4). Technically, fossil fuel can be substituted
fully by alternative non-fossil energy source. Globally, some
cement plants already reached 95 % yearly average. Compared
to global practice, Cementa has a relatively a good performance
in using AF [23]. The use of AF decreased fuel related GHG
emissions of the Swedish cement sector. Energy efficiency
improvement and increased uptake of AF significantly lowered
the CO2 emission intensity from 0.722 - 0.701 tCO2 /t cement
(2010 – 2016) [33].
Swedish cement industry has a roadmap towards fossil free
cement production. The main levers for the roadmap include
energy efficiency improvement, thermal fuel switch, cement
composition (blended cement and/or clinker substitutes), CO2
uptake by concrete, and CCS (see Fig. 5.). According to the
roadmap, CCS technology is expected to provide the largest
CO2 reduction. Currently, CCS technology is under
investigation at Slite plant site to collect over 1.8 Mt of CO2 per
year, it is planned to be commissioned by 2030 [24]. Next to
CCS, biofuel (AF), changes in cement composition, and
concrete CO2 capture moderately contributes to the zero CO2
ambition. EEI has already been exhausted, therefore, it will
have a slight contribution in the roadmap. Furthermore,
CemZero project, which aims for electric heating of clinker
production, is under study in Sweden.
Fig.4.
Fig.5. The zero CO2 ambition
V.
DISCUSSION AND ANALYSIS
A. Energy Performance of Ethiopian Cement Plants
The five year annual electrical and thermal energy
consumption of Ethiopian LCP have been summarized in this
section. The average specific thermal and electrical energy
consumptions are presented in fig. 6 & 7, respectively. The
specific thermal energy consumption is calculated using the
annual clinker production and annual thermal energy
consumption of each plant. In a similar fashion, the specific
electrical energy consumption is calculated using the annual
cement production.
In 2013/14, the average thermal energy intensity was 4.5
GJ/t clinker, which then reduced to 3.76 GJ/t clinker in
2017/18. The average electrical energy intensity was 186.76
KWh/t cement in 2013/14, improved to 138.43 KWh/t of
cement in 2017/18. In general, the intensity of the sector has
shown progress. The thermal energy intensity is improved by
16.4% whereas the electrical intensity by 25%.
As can be seen in Fig. 6 & 7, energy consumption varies
among the plants. This might be due to differences in
production technologies. Some plants are installed with
different modern dry kiln technology, and others are not. For
instance, Dangote, Derba and Mossobo cement plants have
single production line installed with 5 and 6 stage pre-heater
and pre-calciner rotary kiln technology. While, Mughar has
three production lines that have different kiln technologies (5
stage pre-heater, staged pre-heater, and 6 staged pre-heater, and
pre-calciner). On the other hand, National cement plant uses the
old integrated VSK technology. Wide implementation of EEM
throughout the plants may smoothen the disparities in energy
consumption as well as improves their individual intensity.
Share of alternative energy substitutes
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In Ethiopian cement plants, the average clinker substitute
rate is 26.6%. In this regard, Sweden cement plant has lower
substitution rate (less than 10%). Ethiopian cement industry
uses large fraction of Pozzolanic materials (such as
Pumice/Sandstone/Sand) in the production of PPC. On the
other hand, Sweden cement plant uses less fraction of clinker
substituting materials such as blast furnace slag (from steel
production) or fly ash (from Coal processing) to produce
slag/fly ash based Portland cement. Replacing the amount of
clinker or limestone with calcined lime and/or clinker
substituting materials reduces CO2 emission intensity. Table I.
presents summary of the key performance parameters applied
in this study
Fig. 6. Average annual thermal energy intensity in each plant
TABLE I.
No
1
2
3
4
Fig.7. Average annual electrical energy intensity in each plant
B. Energy Performance in Sweden cement plants
In 2013, the global average thermal energy intensity was 3.5
– 3.8 GJ/t clinker while in Cementa, it was 3.7GJ/t clinker at
Slite plant and 4.0 GJ/t of clinker at Skövde plant. Then, due to
progressive implementation of EE measure the average thermal
energy intensity improved to 3.6 GJ/t clinker in 2020. The
electrical energy intensity was 130.6 kwh/t cement in 2020,
higher than the global average of 100 – 110 kwh/t [23].
VI.
COMPARISON BETWEEN ETHIOPIA AND SWEDEN
CEMENT PLANTS
Ethiopian cement plants are more energy intensive
compared to Sweden cement plants. In 2017/18, the average
thermal energy intensity was 3.76 GJ/t clinker in Ethiopian
cement industries while in Sweden it was 3.6 GJ/t clinker in
2020. Likewise, the average electrical energy intensity was
138.93 kwh/t cement in Ethiopian cement plant, in Sweden
cement plants it was 130.6 kWh/t cement in 2020. The average
CO2 emission in Ethiopian cement plants was 0.853t CO2/t
cement in 2018, two years earlier Sweden cement sector
decreased it to 0.701t CO2/t cement. Thus, Sweden cement
sector has better energy and environmental performances
compared to the Ethiopian cement sector. This is due the fact
that, the Sweden cement industry has implemented most of the
cement specific energy efficiency measures/technologies. For
instance, WHRPP has been installed (with a generating
capacity of 8.8 MW) and large amount of fossil fuel was
substituted by AF in the Sweden plants, which were not the case
in Ethiopian cement plants.
5
KEY COMPARISION PARAMETERS
Parameters
Percentage of alternative
fuel/energy used in 2020
Annual Average Specific
thermal energy intensity
(GJ/t of clinker)
Average Specific Electrical
energy intensity
(Kwh/t cement)
Average Specific Electrical
energy intensity
(Kwh/t cement)
Cement
to
clinker
proportion
Ethiopian
cement
Industry
Less than
1%
Swedish
Cement
Industry
62%
3.76
3.6
138.93
130.6
0.853
0.701
26.6%
Less than
10%
VII. CONCLUSION
Cement production consumes large amount of energy and
generates GHGs. Monitoring the energy performance of this
sector is essential from economic and environmental
perspective. This study used different key performance
parameters to compare the Ethiopian and Swedish cement
industries. It has been found that the Swedish cement industry
has a better performance than the Ethiopian. Predominantly,
deployment of WHRPP and replacement of fossil fuel by AF
have improved the electrical and thermal energy consumption
intensity of the Swedish cement industry. The large share of AF
in the fuel mix considerably reduced the CO2 emission of
Sweden cement sector. In Ethiopia, no cement plant deployed
WHRPP and the use of AF in the sector is highly limited.
Furthermore, Sweden cement plants have already put in place a
roadmap for achieving fossil free cement production by 2030.
In this regard, Ethiopia cement sector has no published or
promoted roadmap/strategies for improving energy efficiency
or mitigating CO2 emission. Therefore, it is recommended that
the Ethiopian cement industry and concerned government body
should work in tandem to develop a clear roadmap/strategies
for reducing energy and CO2 intensities.
In conclusion, this study revealed that there is a gap to be
filled by Ethiopian cement industries to be competitive in the
market and also to be environmentally friendly. So much to be
learned from Sweden cement industry in terms of energy and
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the corresponding CO2 emission intensities. Adoption of energy
efficiency measures will enable the Ethiopian cement industry
to close the gap. However, adoption of these measures, for
instance, installation of WHRPP and increasing uptake of
alternative fuel, requires a detailed study in the context of
Ethiopian cement industry. The findings here can be helpful in
applying to many developing countries worldwide.
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