- Dish Stirling engine systems are made of standalone parabolic reflector concentrating light onto a receiver placed at the reflector’s focal point. The reflector follows the sun along two axes.
- Solar Power Tower. This is made up of an array of dual axis tracking reflectors. The mirrors concentrate sunlight on a central receiver which is on top of a tower. The receiver boiler contains fluid which is heated and transferred to a secondary system where it is converted to steam to power a turbine generator. Power towers are efficient and have good energy storage potential.
- Parabolic Trough. Parabolic trough systems are made of a linear parabolic reflector concentrating sunlight onto a receiver tube placed along the reflector’s focal line. The receiver tube is filled with a primary working fluid and transfers heat to a secondary system where it can be converted to steam to power a turbine generator. The reflector tracks the sun during daytime.
- Concentrating Linear Fresnel Reflector. Fresnel reflectors are composed of many flat and thin mirror strips. The system concentrates sunlight onto control tubes containing the primary working fluid. Flat mirrors are expensive than parabolic reflectors and allows more reflective surface area.
Utility Scale Solar Power
Many proposals have been submitted for gigawatt size utility scale solar power plants. Three examples include: The Desertec project; the Project Helios in Greece; and still another one is the Ordos solar plant in China.
To put this vast resource in perspective, the total worldwide energy consumption from all sources is 15,223 TWh each year. A 2003 study concluded that the world can generate 2,357,840 TWh annually from large scale solar power plants alone if all the world’s deserts were used.
Concentrated Solar Power Systems or CSP, is concentrated solar thermal and concentrating solar power which uses lenses and / or mirrors to focus a large area of solar thermal energy onto a small receiving area. When this concentrated light is converted to heat, making steam, electrical power can be generated.
CSP has been widely commercialized and its growth is expected to continue. The CSP market has seen about 740 megawatts of generating capacity added between years 2007 and 2010 alone. CSP is different from CPV or concentrated photovoltaic. CPV concentrates sunlight and convert the light directly to electricity.
CSP is being used to generate electricity. In most cases, the lenses and / or mirrors use tracking systems to increase efficiency and output. The concentrated light is used as a heat source for heating or as a heat source as in a conventional power plant. In CSP, the solar concentrators can also be used to supply industrial process steam for heating, and process cooling.
Four common forms of concentrating technologies