Solar power tower
From Wikipedia, the free encyclopedia
The solar power tower (also known as 'Central Tower' power plants or 'Heliostat' power plants or power towers) is a type of solar furnace using a tower to receive the focused sunlight. It uses an array of flat, movable mirrors (called heliostats) to focus the sun's rays upon a collector tower (the target).
Early designs used these focused rays to heat water, and used the resulting steam to power a turbine. However, designs using liquid sodium in place of water have been demonstrated; this is a metal with high heat capacity, which can be used to store the energy before using it to boil water to drive turbines. These designs allow power to be generated when the sun is not shining.
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[edit] Examples of heliostat power plants
The 10 MWe Solar One and Solar Two heliostat demonstration projects in the Mojave Desert have now been decommissioned. The 15 MW Solar Tres Power Tower in Spain builds on these projects. In Spain the 11 MW PS10 solar power tower and 20 MW PS20 solar power tower[1] have been recently completed. In South Africa, a solar power plant is planned with 4000 to 5000 heliostat mirrors, each having an area of 140 m². A site near Upington has been selected.[2][3]
BrightSource Energy entered into a series of power purchase agreements with Pacific Gas and Electric Company in March 2008 for up to 900MW of electricity, the largest solar power commitment ever made by a utility.[4] BrightSource is currently developing a number of solar power plants in Southern California, with construction of the first plant planned to start in 2009.
In June 2008, BrightSource Energy dedicated its Solar Energy Development Center (SEDC) in Israel's Negev Desert. The site, located in the Rotem Industrial Park, features more than 1,600 heliostats that track the sun and reflect light onto a 60 meter-high tower. The concentrated energy is then used to heat a boiler atop the tower to 550 degrees Celsius, generating steam that is piped into a turbine, where electricity can be produced.[5]
[edit] Cost
The US National Renewable Energy Laboratory NREL has estimated that by 2020 electricity could be produced from power towers for 5.47 cents per kWh.[6] Google.org hopes to develop cheap, low maintenance, mass produceable heliostat components to reduce this cost in the near future. [7]
[edit] See also
[edit] References
- ^ "Spain plugs in largest solar-tower power plant". CNET News. 2009-04-28. http://news.cnet.com/8301-11128_3-10228786-54.html.
- ^ 100 MW Solar Thermal Electric Project in South Africa
- ^ http://www.sabregen.co.za Eskom Website
- ^ "BrightSource Energy signs whopper solar contract with PG&E". CNET News. 2008-03-31. http://news.cnet.com/8301-11128_3-9907089-54.html. Retrieved on 2008-06-11.
- ^ "BrightSource / Luz II Dedicate Negev Solar Energy Development Center". Cleantech Investing in Israel. 2008-06-12. http://cleantech-israel.blogspot.com/2008/06/brightsource-luz-ii-dedicate-negev.html. Retrieved on 2008-06-12.
- ^ Assessment of Parabolic Trough and Power Tower Solar Technology Cost and Performance Forecasts
- ^ Google's Goal: Renewable Energy Cheaper than Coal November 27, 2007
[edit] External links
- Cleantech Group picks winners and losers in concentrated solar thermal
- 'CSP' posts in Green Tech
- eSolar's demonstration plant in Lancaster, Calif.
- National Solar Thermal Test Facility
- Detailed Description of Central Receiver Systems
- Power Station Harnesses Sun's Rays BBC article about solar plant near Seville in Spain
- Description of first commercial Solar Power Tower
- http://pointfocus.com/
- vICERP A research cooperation with a demonstration plant in Juelich, Germany
