Concentrated solar power plants are based on the concentration of solar rays on a fluid. When this fluid reaches the boiling point, the steam that it generates is used to move a turbine and this subsequently generates electricity.
Concentrated solar power works with very high temperatures. Flat collectors are not enough, as high temperatures drop considerably their performance. To generate thermoelectric energy, other devices are used, that allow to concentrate the radiation and maximize the heat generated by the sun. This is not a technology being tested,, rather, its effectiveness is proven, though their installation costs, higher than those of a conventional thermal power plant (based on combustion), is slowing its commercial expansion.
It is formed by curved mirrors, concave channel shaped that concentrates its radiation over a pipeline that carries oil with high temperatures.
This facility consists of a field of heliostats that automatically follow the sun and focus the beam to a receiver located on a tower.
The three main types of thermoelectric power plants are:
Cylindrical-parabolic collectors: they are concave mirrors (curved in the shape of a channel) that concentrate their radiation on a pipe carrying oil. This way, the oil reaches high tempeartures, producing the steam necessary to generate electricity.
Power Plant with central receiver: power plants with central receivers consists of a field of heliostats that automatically follow the sunlight and converge the rays into a fixed light-collecting point or receiver, located on a tower, generating power from 10 to 200 MW.
It is important to distinguish between flat collectors or vacuum tubes, denominated "oflow temperature" and the concentration parabolic collectors (CPC) called "of high temperature". The description "of low temperature", doen't indicate that its temperature is insuficient, but that its performance is what it's needed to provide heating to homes. High temperature collectors, on the other hand, require to reach tempeartures above the boiling point since they are used in power plants that generate electricity through solar thermal energy, for industiral use.
This technology has been tested and confirmed as one of the most promising in the future, lacking only the investment needed, to produce large quantities of electricity. The only limitation is geographical, because, logically, it´s productivity is in function of both, its latitude and climate, therefore, the regions where its future is more promising is in the southwestern U.S., Central America and South Africa, the Middle East, Mediterranean Europe, Iran, Pakistan and the desert regions of India, Russia, China and Australia. Spain by latitude and size, is the European country with the most potential as far as thermal energy is concerned.
Greenpeace says that the production of less than 1% of the global solar thermal potential, would be enough to stabilize the global climate through massive reductions of CO2. The tower power plants and cylindric-parabolic collectors are intended to be used in large projects connected to the grid with a capacity of 10 to 200 MW. Parabolic discs, being modular, can be used in small and large facilities.