Solar Energy Perspectives - IEA

Chapter 8: Solar thermal electricity
Chapter 8
Solar thermal electricity
Solar thermal electricity is a proven technology with close to 30 years of experience. Its
strengths rest in its ability to make electric capacities firm and to time-shift electricity
generation, thanks to thermal storage. STE can also be part of a hybrid plant, lowering the
cost of solar electricity. STE only exists today as concentrating power plants (CSP) in arid and
semi-arid regions. The trend is to increased working temperatures, and to towers with a great
variety of designs and applications. Non-concentrating solar thermal electricity may offer
new options with storage under a greater variety of climates.
Background
In 1878, Augustin Mouchot and Abel Pifre built several concentrating solar systems, based
on dishes, one producing ice in 1878, another the following year running a printing press in
the Jardin du Palais Royal in Paris. They then built small solar desalination plants in Algeria.
The American engineer John Ericsson built similar devices in the United States around 1884,
based on parabolic troughs.
In 1907, Shuman exhibited in Philadelphia a non-concentrating solar motor consisting of
about 100 m 2 of hotbox collectors filled with water and laced with iron pipes containing
ether, which has a relatively low boiling point. Vapour resulting from the solar-heated ether
powered a 560-watt steam engine used to pump a continuous stream of water. Six years later
in Maadi, then a small farming village on the banks of the Nile several miles south of Cairo,
the same Shuman built an irrigation plant run by solar energy, using parabolic trough-shaped
mirrors to concentrate the sun’s rays on water pipes, producing steam running a steam-engine
(Photo 8.1). World War I and the growth of the oil industry ended these developments,
despite the German Parliament voting credits in 1916 for building CSP plants in German
“South-West Africa”, now Namibia.
Electricity was not part of these early attempts, but mechanical power is easily transformed
into electricity. At the time of the first oil shock, several countries developed research
programmes on concentrating solar power, and the IEA launched one of its most successful
“implementing agreements” – Small Solar Power Systems (SSPS), now called SolarPACES,
building a solar tower and a parabolic trough plant in Almeria, Spain. France, Italy, Japan,
Russia, Spain and the United States built experimental solar towers in the early 1980s. From
1984 to 1991 the Luz Company built nine commercial CSP plants in California, most of
which are still up and running today, delivering solar electricity to the grid of the utility
Southern California Edison.
Concentrating solar power
As explained in Chapter 7, concentrating the solar rays allows higher working temperatures
with good efficiency at collector level. This, in turn, allows a better efficiency in the
conversion of the heat into mechanical motion and, thus, electricity, as a consequence of
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© OECD/IEA, 2011