Chuckwalla Valley, near the site of the
proposed 'Desert Sunlight' solar plant.
Published March 10, 2010
Pacific Gas & Electric Co. has signed an agreement to purchase electricity from the proposed Desert Sunlight solar power plant in California's Colorado Desert.
First Solar Inc., based in Tempe, Ariz., is seeking approval from the state and federal governments to construct a 550-megawatt photovoltaic power plant about 6 miles north of a hamlet called Desert Center, which is about 70 miles east of Palm Springs, Calif.
The project, if approved, would become the largest solar power plant under construction in the world. The world's largest solar photovoltaic plant now online is in Spain, and has a peak production capacity of 60 megawatts. A solar PV plant under construction in France is expected to produce up to 143 megawatts. The largest existing solar PV plant in the United States, in Florida, produces up to 25 megawatts.
Solar PV plants convert sunlight directly into electricity using the same types of modules commonly seen on residential and small-business rooftops. They have no moving parts and use no water, except in some instances for periodic cleaning. First Solar has said it would use no water for cleaning modules at the Desert Sunlight project. Photovoltaic projects as large as 2,000 megawatts or more have been proposed in both China and California.
Another type of solar power, called solar thermal technology, uses mirrors to heat fluids and create steam that turns turbines to generate electricity. A third type, called concentrating solar power, employs lenses to focus the sun's rays, and can be used in combination with either photovoltaic or thermal equipment. The world's largest solar thermal project is a collection of power plants in and around Boron, in California's Mojave Desert, which have a peak power-generating capacity of 354 megawatts. Those plants are about 180 miles northwest of the Desert Sunlight project.
The proposed site, overseen by the federal Bureau of Land Management, is crossed by high-voltage power lines and is near the Colorado River Aqueduct, which brings water to the Los Angeles area. Two existing electrical substations are nearby and two would be built to serve the project.
To the northwest of the site, one of the world's largest open-pit iron-ore mines operated until the early 1980s. The massive plateaus of mine tailings are about three miles from the central portion of the proposed solar plant location.
Some environmental groups have opposed the use of this site for a solar plant because it is on habitat favored by desert tortoises, considered a threatened species by both the U.S. and California governments. These animals, which were commonly found as recently as the 1970s on the outskirts of the Los Angeles metropolitan area, are now a scant presence even in remote parts of Southern California. Measures are in place that seek to protect remaining populations, but their effectiveness is not always clear.
Across a paved road from the project site, a few hundred yards away, is the boundary of an area designated by the U.S. Fish and Wildlife Service as a Critical Habitat Unit for the desert tortoise, a place where conservation efforts are to be focused. First Solar plans to construct a fence to keep any tortoises away from the solar installation. Any found within the site before or during construction would be moved, but studies have suggested that mortality rates are high when the animals are moved.
A group called Basin and Range Watch is among those opposed to large-scale solar projects in the desert areas of California and Nevada. The group urges development of rooftop solar projects in urban and suburban areas as a better alternative for solar electricity generation.
The pact between Pacific Gas & Electric and First Solar calls for the utility to buy 300 megawatts of the solar plant's peak production capacity. First Solar had previously signed a contract with Southern California Edison for the other 250 megawatts.
Pacific Gas & Electric, which serves northern and central California customers, is the nation's largest utility in the number of customers served, with about 5.2 million. Southern California Edison, with about 4.8 million customers, is the second-largest.
First Solar estimates that the solar plant would produce enough electricity to provide for the annual needs of as many as 160,000 households, or nearly half a million people.
The project has been fast-tracked by the Bureau of Land Management, and a decision is expected soon. The bureau has said that its fast-track process does not mean a project will receive less attention. A 392-megawatt solar thermal project proposed for the Ivanpah Valley in the Mojave Desert also is under fast-track review.
More information about the Desert Sunlight plan is available in our story, "A Tale of Two Deserts: How Will Solar and Nature Coexist?"
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