Solar Energy Perspectives - IEA

Chapter 8: Solar thermal electricity
Photo 8.4 A parabolic trough and, reflected, the power block of the Integrated solar
combined cycle plant at Ain Beni Mathar, Morocco
Key point
CSP has entered North Africa as integrated solar combined cycle plants.
While for industrialised countries such schemes are more likely to take place on existing
plants, insofar as the solar resource and available land permits, for developing countries it
may also have a place on new-build plants. Although one might feel that hybrid plants are
far from representing a definitive solution to GHG emissions, the reality is that some
developing countries, including two giants – China and India – will remain largely dependent
on coal to face their rapidly growing demand. Building solar-only plants sounds desirable,
but if new coal plants are being built in the same area in the same timeframe, it might be
preferable to built solar-coal hybrids. The same investment in solar fields would displace
additional coal capacity and avoid increasing emissions, and the conversion of the solar
energy into electricity would be more effective.
Smaller plants
For insertion into large grids, the optimal plant size seems to be in the 200 to 300 MWe range
to benefit from scale effects; the most recent projects in the United States tend to target this
range of capacities. Larger projects are made of several projects bundled together.
CSP technologies can also generate electricity on a smaller scale. Below 5 MW, however,
steam Rankine turbines are usually replaced by organic Rankine cycle turbines, which have
a greater efficiency in that power range. The first CSP plant built in the United States since
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© OECD/IEA, 2011