Solar
thermolysis
Solar
thermochemical
cycle
Concentrated
solar energy
Decarbonization
H 2 O splitting
Fossil fuels
(NG, oil, coal)
Solar fuels (hydrogen, syngas)
Solar
electricity
+
electrolysis
Solar
reforming
Solar
cracking
H 2 O
Optional CO 2 /C
sequestration
Solar
gasification
0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
Carnot
T optimum
1,000
5,000
10,000
20,000
40,000
Exergy efficiency
100%
50%
0%
0
500
1000
1500
2000
2500
3000
3500
4000
Temperature (K)
FIGURE 11.1 Thermochemical routes for solar hydrogen production. (From Meier, A. and
Sattler, C., “Solar fuels from concentrated sunlight,” SolarPACES, Solar Power and Chemical
Energy Systems, IEA report, 2009. With permission.)
FIGURE 11.2 Exergy efficiency—Variation of the exergy efficiency as a function of the
process operating temperature for a blackbody cavity receiver converting concentrated solar
energy into chemical energy. (From Meier, A. and Sattler, C., “Solar fuels from concentrated
sunlight,” SolarPACES, Solar Power and Chemical Energy Systems, IEA report, 2009. With
permission; Fletcher, E.A. and Moen, R.L., Science, 197, 1050–1056, 1977. With permission.)