Concentrating Solar Power Systems

       Concentrating solar collectors

Solar concentrators work by focusing sunlight onto a tube containing a liquid such as water or often a molten salt solution. The super-heated solution is then used to produce steam to generate electricity or often to perform other energy-intensive work in industrial applications.

Case Study: Solar I and Solar II

Solar I and Solar II were molten-salt solar power plants that operated by using 2000 large, sun-tracking heliostats to concentrate sunlight onto a receiver resting atop a tower. Inside the receiver, a molten salt solution is heated to 1050 degrees F.  The superheated salt solution is piped away, stored, and used when needed to produce steam. The steam then drives a turbine/generator that produces electricity. The salt solution is a mix of sodium and potassium nitrate, which has excellent heat-absorption qualities and is said to be environmentally safe.  

          Solar I

      Solar I operated from 1982-1988 in Sandina, CA. Solar I made use of a water / steam system that was unable to store energy efficiently. It proved to be impractical to operate the system on cloudy days or after nightfall.  

         Solar II

            In 1996 the DOE and Southern California Edison funded Solar II in Daggett, CA.  Solar II is located about 10 miles from Barstow. It can produce 10 MW of electricity, enough power to supply 10,000 homes.  

         Future of solar power towers

            In the future, solar power  towers may be able to generate 10 to 20 times the electricity of Solar II.  How this will compare in terms of cost-effectiveness remains to be seen. Though the success of Solar I and II has taken us a step closer to making solar a viable contributor in the electricity generation market, vast agreement remains that the best way to make use of this resource is not in the large-scale, centralized form of the solar power tower.