Solar Hydrogen
Stellenbosch University, September 2nd, 2010
Dr. Christian Sattler
DLR – German Aerospace Center - Solar Research
e-mail: christian.sattler@dlr.de
Slide 1
Stellenbosch University > 2 Sept. 2010
Overview
Introduction of DLR
Energy
Solar Hydrogen
From Fossil
Recourses
Thermochemical
Cycles
HYDROSOL,
HYDROSOL 2,
HYDRSOOL 3-D
Summary and Outlook
Slide 2
Stellenbosch University > 2 Sept. 2010
DLR
German Aerospace Center
Research Institution
Space Agency
Project Management Agency
Slide 3
Stellenbosch University > 2 Sept. 2010
Research Areas
Aeronautics
Space
Transport
Energy
Space Agency
Project Management Agency
Slide 4
Stellenbosch University > 2 Sept. 2010
Locations and employees
6500 employees across
29 research institutes and
facilities at
 13 sites.
Offices in Brussels,
Paris, Washington, and Almería
(plus permanent Delegation on the
Plataforma Solar de Almería)
Hamburg 
Bremen 
 Neustrelitz
 Trauen
Berlin 
Braunschweig 
 Dortmund  Goettingen
 Koeln
 Bonn
Lampoldshausen 
Stuttgart 
 Oberpfaffenhofen
Weilheim 
Slide 5
Stellenbosch University > 2 Sept. 2010
Energy
Slide 6
Stellenbosch University > 2 Sept. 2010
DLR Energy Research Area
DLR Energy Research concentrates
on:
CO2 avoidance through
efficiency and renewable
energies
synergies within the DLR
major research specific themes
that are relevant to the energy
economy
Second largest research centre
in Germany for non-nuclear
energy
Approx. 400 employees
Slide 7
Stellenbosch University > 2 Sept. 2010
Energy Research Program Themes
Efficient and environmentally
compatible fossil-fuel power
stations
(turbo machines, combustion
chambers, heat exchangers)
Solar thermal power plant
technology, solar materials
conversion
Thermal and chemical energy
storage
High and low temperature fuel
cells
Systems analysis and
technology assessment
Slide 8
Stellenbosch University > 2 Sept. 2010
Efficient
energy
conversion
Renewable
energies
Systems analysis and technology assessment
Portfolio of Competences – Energy
Fuel cells
Power plant
technology
Concentrating
solar systems
Materials
Combustion
Manufacturing
techniques
Turbo-machines
Heat management
Gas turbine systems
Heat exchangers
Hybrid power plants
Solar gas turbines
Fuel cells
with alternative fuels
Solar gas turbines
Heat storage
Gas turbines with
alternative
fuels
Solar hydrogen
production
Solar power plants
Solar process heat
Simulation/modelling
Slide 9
Stellenbosch University > 2 Sept. 2010
Solar Hydrogen
Slide 10
Stellenbosch University > 2 Sept. 2010
Vision
Producing hydrogen for mass markets means implementing as
efficient processes as possible to convert available energy
sources like renewables or nuclear into the chemical energy
vector.
(De Beni G. 1970; Marchetti 1973; Winter 2000)
Hydrogen should be produced from water
to reduce dependencies on fossil fuels
To reduces environmental impact
Slide 11
Stellenbosch University > 2 Sept. 2010
Technical and Economic Efficiency
Technical:
In which process is the most energy stored in the
hydrogen
Is the process technical feasible?
Are there any knock-out criteria?
Economic:
Is the product (hydrogen) cost competitive?
Are there any other economic reasons that make the
process not competitive?
Slide 12
Stellenbosch University > 2 Sept. 2010
Hydrogen Production Today
Steam Methane Reforming
Thermal efficiency 78%
1 kg H2 by means of SMR yields to 9.42 kg of CO2
The production cost of hydrogen is estimated at 0.04 €/kWh (1.33 €/kg)
Coal Gasification
The Lurgi Process (Fixed-Bed) 500 – 1000 °C
The Winkler Process (Fluidized-Bed) 800 - 1100 °C
The Koppers-Totzek/Texaco Process (Entrained-Bed) 1040 – 1540 °C
Thermal efficiency 58 - 63%
23 kg CO2 / kg H2
Hydrogen costs from coal gasification are 1.21 to 1.79 €/kg H2(coal price
not reported)
Partial Oxidation
1300 - 1500 °C
1.45 – 1.67 €/kg
Slide 13
Stellenbosch University > 2 Sept. 2010
Solar Thermal Processes for Hydrogen Production
Today:
Industrial-scale
Cheap
Not renewable
Future:
Renewable
Expensive
Slide 14
Stellenbosch University > 2 Sept. 2010
Production-, Storage- and Infrastructure topics of the
European Hydrogen and Fuel Cell JTI
Slide 15
Stellenbosch University > 2 Sept. 2010
Solar Hydrogen from Hybrid Fossil Processes
Slide 16
Stellenbosch University > 2 Sept. 2010
Carbon Based Transition Processes
Starting from applied technologies
Reduced risk compared to water splitting technologies
Solar Reforming of Natural Gas
Development by a number of groups since at least 25 years
Cost are estimated to 1.4 €/kg H2
Solar Gasification and Reforming of Petcoke
Development by ETH Zurich, CIEMAT, and PDVSA
Cost are estimated to about 2.1 €/kg H2
SOLZINC – Carbothermal reduction of ZnO
Pilot reactor successfully tested
Zinc is produced not hydrogen!
Solar Cracking of Methane
No CO2 emission but C, C might be a product too
challenging reactor design: solids and high temperatures
Slide 17
Stellenbosch University > 2 Sept. 2010
Solar Steam Methane Reforming – Technologies
decoupled/allothermal
indirect (tube reactor)
Integrated, direct,
volumetric
Quelle: DLR
Reformer heated externally
(700 to 850°C)
Optional heat storage ( up
to 24/7)
E.g. DLR Project ASTERIX
Irradiated reformer tubes (up to
850°C), temperature gradient
Catalytic active direct
irradiated absorber
Approx. 70 % Reformer-
Development: CSIRO,
Australia and in Japan;
Research in Germany and
Israel
Australian solar gas plant
in preparation
Approx. 90 % Reformer-
High solar flux, works only
by direct solar radiation
DLR coordinated projects:
SCR, Solasys, Solref;
Research in Israel, Japan
Slide 18
Stellenbosch University > 2 Sept. 2010
Direct heated volumetric receiver:
SOLASYS, SOLREF (EU FP4, FP6)
Pressurised solar receiver,
Developed by DLR
Tested at the Weizmann
Institute of Science, Israel
Power coupled into the process
gas: 220 kWth and 400 kWth
Reforming temperature:
between 765°C and 1000°C
Pressure: SOLASYS 9 bar,
SOLREF 15 bar
Methane Conversion:
max. 78 % (= theor. balance)
DLR (D), WIS (IL), ETH (CH),
Johnson Matthey (UK), APTL
(GR), HYGEAR (NL), SHAP (I)
Slide 19
Stellenbosch University > 2 Sept. 2010
Assessment of relevant H2 pathways until 2020
including NG Solar-SMR for comparison issues
NG
NG
Grid Electricity
Wind
SMR
SolarSMR
electrolysis
electrolysis
8*
12*
€/GJ
€/GJ
31 €/GJ
50-67 €/GJ
25-33 €/GJ
Positive impact on
security of energy
supply
modest
modest high
high
high
high
Positive impact on
GHG emission
reduction
neutral modest
modest - high
negative -neutral
high
high
H2 production cost
Biomass
*assuming a NG price of 4€/GJ; NG Solar-SMR: expected costs for large scale, solar-only
Slide 20
Stellenbosch University > 2 Sept. 2010
Project Perspectives
The consortium forces the
realisation of the a prototype
reforming plant
Link with Australian CSIRO by an
ongoing IPHE project
Funding was assured in October
2009
Development phase of the joint
project
SOLREF receiver will run on a
second tower at the CSIRO Solar
Centre in Newcastle, NSW
Slide 21
Stellenbosch University > 2 Sept. 2010
Thermochemical Cycles
Slide 22
Stellenbosch University > 2 Sept. 2010
Thermochemical Water Splitting
2500 °C
H
H
O
100 °C
0 °C
- 273 °C
Slide 23
Stellenbosch University > 2 Sept. 2010
PROBLEMS!
Hydrogen + Oxygen = explosive gas!
Dangerous
Separation?
2500 °C Materials
Special ceramics – difficult to handle, expensive
2500 °C Temperature
How could such high temperatures be achieved?
Efficiency?
Slide 24
Stellenbosch University > 2 Sept. 2010
Sollution
H2 + O2
2500 °C
H2
O2
850 °C
1250 °C
Are the problems solved now?
•Still high temperatures
H2O
•Materials
H2O
•Chemical reactions
•Efficiency
Slide 25
Stellenbosch University > 2 Sept. 2010
Thermochemical Cycle
Firstly developed in the oil crises of the 1970s
Use of nuclear energy to produce an energy carrier
Mainly in the USA (General Atamics, Westinghouse), but also in Europe (FZJ,
JRC Ispra) and Japan (JAEA)
Up to 900 different cycles are known
Main groups:
Sulphur cycles
Volatile metal oxide cycles
Non-volatile metal oxie cycles
Low temperature cycles
In the 1980s and 1990s the interst went down because of lower oil prices
Come back in the 2000s
Solar thermal more in the focus
Studies to identify the most promising cycles (e.g. USA, France)
Slide 26
Stellenbosch University > 2 Sept. 2010
Thermochemical vs. Electrochemical?
Thermochemical
No conversion steps necessary = possibly very high efficiency
Electrochemical
Conversion steps necessary for power production = lower
efficiency
No contradiction: use energy forms as efficient as possible
Slide 27
Stellenbosch University > 2 Sept. 2010
Promising and well researched Cycles
Steps
Maximum Temperature LHV Efficiency
(°C)
(%)
Sulphur Cycles
Hybrid Sulphur (Westinghouse, ISPRA
Mark 11)
2
900 (1150 without
catalyst)
43
Sulphur Iodine (General Atomics, ISPRA
Mark 16)
3
900 (1150 without
catalyst)
38
2
1800
45
1600
42
Volatile Metal Oxide Cycles
Zinc/Zinc Oxide
Hybrid Cadmium
Non-volatile Metal Oxide Cycles
Iron Oxide
2
2200
42
Cerium Oxide
2
2000
68
Ferrites
2
1100 – 1800
43
4
530
39
Low-Temperature Cycles
Hybrid Copper Chlorine
Slide 28
Stellenbosch University > 2 Sept. 2010
Temperature nuclear
Reactor Type
Temperature
(°C)
Carnot-Efficiency
Boiling Water Reactor
285
47%
RBMK (Graphite moderated)
285
47%
CANDU Reactor (Heavy
Water Reactor)
300
48%
Pressurised Water Reactor
320
50%
Breeder Reactor, Sodium
cooled
550
64%
Advanced Gas Cooled
Reactor
650
68%
(Very) High Temperature
Reactor
750+
71+%
Slide 29
Stellenbosch University > 2 Sept. 2010
Temperature – Concentrating Solar Power
3500 °C
Paraboloid: Dish
1500 °C
400 °C
Solar tower
(Central Receiver System)
150 °C
50 °C
Parabolic trough
Slide 30
Stellenbosch University > 2 Sept. 2010
Annual Efficiency of Solar Power Towers
Optical efficiency and thermal annual use
efficiency [%]
Power Tower 100MWth
Optical and thermal efficiency / Receiver-Temperature
50
45
40
35
30
25
20
15
10
5
0
600
700
800
900
1000
1100
Receiver-Temperature [°C]
1200
1300
1400
R.Buck, A. Pfahl, DLR, 2007
Slide 31
Stellenbosch University > 2 Sept. 2010
Solar Towers, “Central Receiver Systems”
Solar-Two
PSA
PS10+20
Slide 32
Stellenbosch University > 2 Sept. 2010
Efficiency comparison solar H2 production from
water, SANDIA 2008
Process
T
[°C]
Solar plant
Solarreceiver
+ power
[MWth]
η
T/C
(HHV)
η Optical
η
Receiver
η
Annual
Efficiency
Solar – H2
Elctrolysis (+solarthermal power)
NA
Actual
Solar tower
Molten
Salt
700
30%
57%
83%
14%
High temperature
steam electrolysis
850
Future
Solar tower
Particle
700
45%
57%
76,2%
20%
Hybrid Sulphurprocess
850
Future
Solar tower
Particle
700
51%
57%
76%
22%
Hybrid Copper
Chlorine-process
600
Future
Solar tower
Molten
Salt
700
49%
57%
83%
23%
Nickel Manganese
Ferrit Process
1800
Future
Solar dish
Rotating
Disc
<1
52%
77%
62%
25%
G.J. Kolb, R.B. Diver SAND 2008-1900
Slide 33
Stellenbosch University > 2 Sept. 2010
Water based processes
Long term necessary for the de-carbonised H2 society
Benchmark: Renewable electricity + electrolysis
Challenging technologies
Metal/Metal oxide thermo-chemical Cycles
Zn/ZnO (3,58 – 4,12 €/kg)
Mixed Iron Oxides (Ferrites)
Already shown in the HYDROSOL project
Cost based on the small scale experiments are 7 €/kg
Calculated improvements will lead to 3,5 €/kg
Sulphur Cycle Family
Developed for use with nuclear heat
Hybrid Sulfur (ISPRA Mark 11)
Cost calculation 0,8 €/kg H2 nuclear
Sulphur-Iodine Process (ISPRA Mark 16)
Cost calculation 1,17 – 1,66 €/kg nuclear, 4,53 €/kg solar
Slide 34
Stellenbosch University > 2 Sept. 2010
HYDROSOL, HYDROSOL 2, HYDROSOL 3D
Slide 35
Stellenbosch University > 2 Sept. 2010
Thermochemical Cycle using Mixed Iron Oxides
Process Operation
1. Step: Water Splitting
H2O + MOred  MOox + H2
H2O
MO
MO
H2 red
O
ox
2
800 – 1200 °C
2. Step: Regeneration
MOox  MOred + ½ O2
O2red
MO
MO
ox
1200°C
Net reaction: H2O  H2 + ½ O2
Redox materials used in the
HYDROSOL-2 project:
ZnFeO, NiZnFeO
Slide 36
Stellenbosch University > 2 Sept. 2010
Reactor for continuous hydrogen production:



Reactor with two modules
15 kW two-chamber system
Two different alternating processes:
•
Production: 800°C, water steam,
nitrogen, exothermic
Regeneration: 1200°C, nitrogen,
endothermic
Transient steps like
•
Switching between half cycle
•
Start-up / Shutdown
Closed system: quartz window
Four-way-valve
1200°
800° C
H
O2+N2
•



H2+N2
O
1200°
800° C
Slide 37
Stellenbosch University > 2 Sept. 2010
HYDROSOL II Pilot Reactor in Operation
Slide 38
Stellenbosch University > 2 Sept. 2010
Experiments – Process Control Software:
Set parameter
Solar Power
Process-Flow-Sheet
Regeneration
N2
N2
H2O
Production
Slide 39
Stellenbosch University > 2 Sept. 2010
Experiments – Process Control Software:
Flux Measurement at test operation
FluxMaxboth Modules= 115kW/m2
Slide 40
Stellenbosch University > 2 Sept. 2010
Results: Thermal cycling
Slide 41
Stellenbosch University > 2 Sept. 2010
16:54:56:40
16:45:13:87
16:34:38:90
16:23:59:71
16:13:29:14
16:02:50:15
15:52:11:10
15:41:34:09
15:30:54:76
15:20:15:14
15:09:48:46
14:59:09:28
14:48:38:73
14:38:43:34
14:28:13:50
14:17:45:50
14:07:44:28
13:57:08:35
13:46:39:26
13:36:25:34
13:25:49:78
13:15:38:89
13:05:27:85
12:55:09:93
12:45:16:01
12:35:25:87
12:25:34:45
12:15:39:75
12:05:54:21
11:56:01:18
11:46:05:43
11:36:48:32
11:27:39:00
11:18:29:71
11:09:20:68
11:00:11:62
10:51:02:50
10:41:52:96
10:32:44:07
10:23:35:20
10:14:25:00
c(H2) [%]
Hydrogen production of 4th day of experimental
series
9
8
7
6
5
4
3
2
1
0
Stellenbosch University > 2 Sept. 2010
Slide 42
Summary and Outlook
• Technologies like solar steam reforming should be short term
technologies to introduce solar technology into the chemical
industry
• Thermochemical cycles will provide renewable hydrogen with
very high efficiency compared to other renewable technologies
• The HYDROSOL reactor concept was scaled up in
HYDROSOL 2 from the solar furnace to a 100 kW pilot plant on
the tower of the PSA
• Topic of the ongoing HYDROSOL 3-D project is the design of a
MW test plant
• Also sulfur cycles should be scaled-up since the development
is already on a very advanced level and the temperature level
is lower than of other TCCs
Slide 43
Stellenbosch University > 2 Sept. 2010
Acknowledgement
The Projects
HYDROSOL, HYDROSOL II; HYTHEC,
HYCYCLES, Hi2H2, INNOHYP-CA,
SOLHYCARB und SOLREF are co-funded by
the European Commission
HYDROSOL 3-D is co-funded by the European
Joint Technology Initative on Hydrogen and
Fuel Cells
HYDROSOL was awarded
Eco Tech Award Expo 2005, Tokyo
IPHE Technical Achievement Award
2006
Descartes Research Price 2006
Slide 44
Stellenbosch University > 2 Sept. 2010
Thank you very much for your attention!
Slide 45
Stellenbosch University > 2 Sept. 2010