Operational Solar Thermal Power Stations

Nevada Solar One is the second largest concentrated solar power plant  in the world, with a nominal capacity of 64 MW and maximum capacity of 75 MW, as of June 2007. The project required an investment of $266 million USD and electricity production is estimated to be 134 million kilowatt hours per year.[
It is the second solar thermal power plant built in the United States in more than 16 years and the largest STE plant built in the world since 1991. It is on the southeast fringes of Boulder City, Nevada. It was built by Acciona Solar Power (formerly Solargenix), a partially owned subsidiary of Spanish conglomerate Acciona Energy. Acciona purchased a 55 percent stake in Solargenix and owns 95 percent of the project. Nevada Solar One is unrelated to the Solar One power plant in California.

Nevada Solar One uses 760 parabolic troughs (using more than 180,000 mirrors) made by Flabeg AG in Germany[9] that concentrate the sun's rays onto thermos tubes running laterally through the troughs and containing a heat transfer fluid (solar receivers), in contrast to the power tower concentrator concept that California's original Solar One project uses.

Given Nevada's land and sun resources the state has the ability to produce more than 600 GW using solar thermal concentrators like those used by Nevada Solar One.

Solar power towers use thousands of individual sun-tracking mirrors (called heliostats) to reflect solar energy onto a central receiver located on top of a tall tower. The receiver collects the sun's heat in a heat-transfer fluid that flows through the receiver. The U.S. Department of Energy, and a consortium of U.S. utilities and industry, built the first two large-scale, demonstration solar power towers in the desert near Barstow, CA.

Solar One operated successfully from 1982 to 1988, proving that power towers work efficiently to produce utility-scale power from sunlight. The Solar One plant used water/steam as the heat-transfer fluid in the receiver; this presented several problems in terms of storage and continuous turbine operation. To address these problems, Solar One was upgraded to Solar Two, which operated from 1996 to 1999. Both systems had the capacity to produce 10 MW of power. The unique feature of Solar Two was its use of molten salt to capture and store the sun's heat. The very hot salt was stored and used when needed to produce steam to drive a turbine/generator that produces electricity. The system operated smoothly through intermittent clouds and continued generating electricity long into the night.

California's Mojave Desert - Solar Energy Generating Systems (SEGS) is the largest solar energy generating facility in the world. It consists of nine solar power plants.

The plants have a 354 MW installed capacity, making it the largest installation of solar plants of any kind in the world.[1] By comparison, the largest photovoltaic plant, which is in Spain, produces 60 MW, although a 62 MW PV installation (Moura photovoltaic power station) is under construction in Portugal[2] and a 154 MW PV Solar power station in Victoria  Australia, is planned.

The average gross solar output for all nine plants at SEGS is around 75 MWe — a capacity factor of 21%. In addition, the turbines can be utilized at night by burning natural gas.

The facilities have a total of 936,384 mirrors and cover more than 1,600 acres (6.5 km2). Lined up, the parabolic mirrors would extend over 229 miles (370 km).

The parabolic mirrors are shaped like a half-pipe. The sun shines onto the panels made of glass, which are 94% reflective, unlike a typical mirror, which is only 70% reflective. The mirrors automatically track the sun throughout the day. The greatest source of mirror breakage is wind, with 3000 typically replaced each year. Operators can turn the mirrors to protect them during intense wind storms.

SEGS III–VII (150 MW) are located at Kramer Junction, SEGS VIII–IX (160 MW) at Harper Lake, and SEGS I–II (44 MW) at Daggett respectively.[1]The SEGS power plants were built by Luz Industries,[6] and commissioned between 1984 and 1991. Kramer Junction employs about 95 people and 45 people work at Harper Lake.