California Utility Agrees to Buy 553 Megawatts of Solar Power

August 1, 2007

Photo of a parabolic trough system, which is described in the caption. In the foreground are pipes that distribute the heat-transfer fluid to each of the receiver tubes.

Parabolic trough systems consist of a trough-shaped mirror that focuses sunlight onto a "receiver" tube. A fluid is pumped through the receiver tube to collect the solar energy.
Credit: Henry Price

Pacific Gas and Electric Company (PG&E) announced on July 25th that it has agreed to buy power from a 553-megawatt solar thermal power plant to be located in California's Mojave Desert. Solel-MSP-1 plans to build the Mojave Solar Park using its parabolic trough technology, which employs long rows of trough-shaped mirrors that concentrate the sun's heat onto a "receiver" tube. The vacuum-insulated tubing carries a fluid that is heated to high temperatures and is then used to boil water. The steam drives a turbine and generator to produce power. The Solel facility will cover about 9 square miles, featuring 1.2 million mirrors and 317 miles of vacuum tubing. When fully operational in 2011, the Mojave Solar Park will produce enough electricity to meet the average annual needs of 400,000 homes in PG&E's service territory. The new contract is the largest solar power agreement in the world. See the PG&E press release.

In recent years, California utilities have signed a number of agreements to buy electricity from solar thermal power plants, but none of the new facilities have yet to materialize. Last year, PG&E signed an agreement with another parabolic trough company for 500 megawatts of solar thermal power. In 2005, PG&E's neighbors to the south—Southern California Edison and the San Diego Gas and Electric Company—signed on for 500 megawatts and 300 megawatts of solar thermal power, respectively. Those projects intended to deploy arrays of dish-shaped mirrors that focus sunlight onto Stirling heat engines. See the article from the August 16th, 2006, edition of the EERE Network News.

While California utilities have big plans for solar thermal power, the Electric Power Research Institute (EPRI) is leading a new project to study the feasibility of building a solar thermal power plant in New Mexico. The project will involve establishing a team of experts from electric utilities, engineering firms, and DOE national laboratories, including the National Renewable Energy Laboratory and Sandia National Laboratories. That team will perform a feasibility study for a solar thermal plant that will be 50 to 500 megawatts in capacity. The study will be finished by the end of this year, and if it finds the project to be feasible, the project will advance to a design and permitting phase, followed by a construction phase. EPRI is working on the project with PNM, a utility in New Mexico, as well as several other utilities that operate in the Southwest. See the EPRI press release.