Solar Trough - Commercial Power from The Sun.

Parabolic trough systems predominate among today’s commercial solar power plants.   Trough systems convert the heat from the sun into electricity. Because of their parabolic shape, troughs can focus the sun at 30 to 60 times its normal intensity on a receiver pipe located along the focal line of the trough. Synthetic oil captures this heat as the oil circulates through the pipe, reaching temperatures as high as 390°C (735ºF). The hot oil is pumped to a generating station and routed through a heat exchanger to produce steam. Finally, electricity is produced in a conventional steam turbine.

     The solar trough system is used in many places. In the U.S., California, Nevada and Arizona are current and future sites for commercial solar trough stations.  One of the biggest in the U.S. is Kramer Station in San Bernadino CA.

New parabolic trough systems are being built around the world. Some examples are:

RMT Roof Mounted Trough - Fort Sam Houston
The RMT trough system at Fort Sam Houston, San Antonio, Texas came on line in June 2003. It provides solar thermal energy to a pressurized water district-heating loop that delivers heat for showers, building space heat and air-conditioning reheat to a number of buildings at the Army medical base.

UNLV/DoE Solar Site - Boulder City Nevada
Solargenix is constructing a 64 MW solar plant near Boulder City, Nevada, that utilizes an advanced parabolic trough design.  This project was initiated to test some of the necessary component engineering work prior to the start of the 64 MW plant installation.  As part of the work, two Solar Collector Assemblies (SCA’s) are being erected, exclusive of the receiver tubes and only partially outfitted with parabolic mirrors, so that mechanical testing can be completed, proper fit and function can be demonstrated, and installation methods can be verified and improved.  Receivers and additional parabolic mirrors may be added at a later time so that the SCA’s can also be tested for thermal performance in the future.  Included in the equipment to be tested at the site are Advanced Local Controllers (AdLoC’s), which have been newly developed, to control the sun tracking of the parabolic troughs using a new hydraulic-based drive system.

Andasol I, II, III - Granada Spain
Andasol 1 Project implementation: June 2006 - June 2008
Andasol 2 Project implementation: March 2007 - March
Andasol 3 Project implementation: Start of construction planed for 1 Quarter 2008

• Contribute with the production of 157.4 million kWh per year of pure solar energy to fulfill the commitments Spain has assumed in Kyoto to the reduction of emissions
• Provide this solar electricity without fluctuation or interruption, thanks to the 7 hour storage, maintaining the stability of the electric grid
• Avoid the emission of 152 million kilos of CO2 per year to protect the climate and the environment
• Create about 50 permanent jobs for operation and maintenance of the AndaSol-1 project, employing up to a maximum of 500 workers during the construction period of approximately two years
• Make maximum use of the local resources of labor and construction material supply in an economically depressed region
• Develop the basis for experience and infrastructure of a promising resource of renewable energy, thus leading to additional opportunities of employment and fabrication

     Many countries are currently investigating parabolic power stations as a supplimental power to their current system. The object is to ween current systems off fossil fuels. Kramer station still runs on fossil fuels at night, though the parabolic system has now cut fossil fuel usage to 27%.