Survey of Energy Resources 2007
Solar Thermal Power Plants
Concentrating solar collectors can achieve temperatures in the range of 3000C to 1 0000C or even higher, which is ideal for generating electricity via thermodynamic power cycles. All of the present power plants based on fossil fuels and nuclear power work on the same principles. Therefore this technology takes advantage of the knowledge base relating to conventional power plants. Another advantage of Solar Thermal Power is that it can easily use fossil fuels such as natural gas as a back-up fuel or store high-temperature heat to overcome the disadvantage of the intermittency of sunlight. Fig. 10-12 explains the concept of a solar thermal power plant operating with storage and/or a backup fuel. Fig. 10-13 shows schematic diagrams of the types of concentrating solar collector used for solar thermal power plants.
Solar thermal power plants use direct sunlight, so they must be sited in regions with high direct solar radiation, as those shown in Fig. 10-14 .
Among the most promising areas are the south-western United States, Central and South America, Africa, the Middle East, the Mediterranean countries of Europe, south Asia, certain countries of the Former Soviet Union, China and Australia.
CSP capacity of 364 MW was installed in California in 1990 (Figs. 10-15 and 10-16 ), most of which (354 MW) is still operating. Each year the performance of the plant has improved, due to the learning experience and better operations and maintenance procedures. This power plant is based on parabolic-trough technology, with natural gas as a backup fuel. Although investments in new solar power plants ceased for a while because of a lack of R&D and favourable policies, recently there has been a resurgence of interest in this technology. A number of plants are under construction or in the planning stage around the world, which when completed, will increase worldwide capacity to about 3 000 MW. Of this, more than 2 000 MW will be in Spain, because of the excellent solar resource and favourable government policies.
A new generation of solar power systems is under development in various parts of the world. Trough technology with direct steam generation is under experimentation at the Plataforma Solar de Almería, part of the Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT) on Spain's Mediterranean coast. Much the greater part of the research and commercial activity on solar thermal power is happening in Spain.