The Ivanpah Solar Electric Generating System is a concentrated solar thermal plant located in the Mojave Desert at the base of Clark Mountain in California, across the state line from Primm, Nevada. Opened in 2014, it was slated to close in 2026, but that decision was reversed by the California Public Utilities Commission. The facility derives its name from its proximity to Ivanpah, California, which lies within the Mojave National Preserve in San Bernardino County and which derives its name from the Chemehuevi word for "clean water". The plant has a gross capacity of 392 megawatts (MW). It uses 173,500 heliostats, each with two mirrors focusing solar energy on boilers located on three 459-foot-tall (140 m) solar power towers. The first unit of the system was connected to the electrical grid in September 2013 for a synchronization test. The facility formally opened on February 13, 2014. At that time, it was the world's largest solar thermal power station. The $2.2 billion facility was developed by BrightSource Energy and Bechtel. The largest investor in the project was NRG Energy which contributed $300 million. Google contributed $168 million. The United States government provided a $1.6 billion loan guarantee and the plant is built on federal land. In 2010, the project was scaled back about 10% from its original 440 MW design to avoid disturbing the habitat of the desert tortoise. In January 2025, the plant's co-owner NRG Energy announced it was unwinding power purchase agreements with Pacific Gas & Electric Company and Southern California Edison and, subject to regulatory approval, would begin closing the plant in early 2026, readying the site to potentially be repurposed for a different type of solar energy. The facility, though cost effective when it was planned in 2009, became twice as expensive to run as solar photovoltaic technology, which has decreased in price much more rapidly than was expected in the years since Ivanpah's construction. The power companies purchasing electricity from Ivanpah said that they expect the closure will save their ratepayers money. NRG declined to say how much of the $1.6 billion loans guaranteed by the government remained unpaid as of 2025. In December 2025, the closure agreement was unanimously rejected by the California Public Utilities Commission.
Description
The Ivanpah system consists of three solar thermal power plants on 3,500 acres (1,400 ha) of public land near the California–Nevada border in the Southwestern United States. Initially it was planned with 440 MW gross on 4,000 acres (1,600 ha) of land, but then downgraded by 12%. It is west of south Interstate 15, north of Ivanpah, California, and adjacent to the Mountain Pass mine, the United States' only source of rare-earth minerals. The facility is visible from the I-15, the adjacent Mojave National Preserve, the Mesquite Wilderness, and the Stateline Wilderness. It is also visible from the Primm Valley resort area to the northeast. Fields of heliostat mirrors focus sunlight on receivers located on centralized solar power towers. The receivers generate steam to drive specially adapted steam turbines. For the first plant, the largest-ever fully solar-powered steam turbine generator set was ordered, with a 123 MW Siemens SST-900 single-casing reheat turbine. Siemens also supplied instrumentation and control systems. The plants use BrightSource Energy's "Luz Power Tower 550" (LPT 550) technology which heats the steam to 550 °C directly in the receivers. The plants have no storage. Final approval for the project was granted in October 2010. On October 27, 2010, Governor of California Arnold Schwarzenegger, Interior Secretary Ken Salazar, and other dignitaries gathered in the Mojave Desert to break the ground for the construction.
The largest investor in the project was NRG Energy, a generating company based in Princeton, New Jersey. It contributed $300 million. The project also received an investment of $168 million from Google. In November 2011, Google announced that it would no longer invest in the facility due to the rapid decline of the price of photovoltaic systems. $90,000,000 in financing was provided through the EB-5 Investor Immigration program, managed in this case by CMB Regional Centers. The project, which had a total cost of about $2.18 billion, received a $1.6 billion loan guarantee from the United States Department of Energy. The facility developed contracts to sell about two-thirds of the power it generated to the Pacific Gas and Electric Company (PG&E), and the rest to Southern California Edison (SCE). PG&E announced in 2025 that it was terminating its contracts subject to approval by regulators. In December 2025, the CPUC unanimously rejected that agreement, citing concerns about grid reliability and wasting sunk costs. The decision requires two of the three units to remain running.
Fossil fuel consumption The plant burns natural gas each morning to commence operation. The Wall Street Journal reported, "Instead of ramping up the plant each day before sunrise by burning one hour's worth of natural gas to generate steam, Ivanpah needs more than four times that much." On August 27, 2014, the State of California approved Ivanpah to increase its annual natural gas consumption from 328,000,000 cubic feet (9,300,000 m3) of natural gas, as previously approved, to 525,000,000 cubic feet (14,900,000 m3). In 2014, the plant burned 868×109 British thermal units (254 GWh) of natural gas emitting 46,084 metric tons of carbon dioxide, which is nearly twice the pollution threshold at which power plants and factories in California are required to participate in the state's cap and trade program to reduce carbon emissions. If that fuel had been used in a Combined Cycle Gas Turbine (CCGT) plant, it would have generated about 124 GWh of electrical energy. The facility used that gas plus solar energy to produce 419 GWh of electrical energy (more than three times that of the referenced CCGT plant), all the while operating at well below its expected output. In 2015, the facility showed higher production numbers, with Q1 increases of 170% over the same time period in 2014. The facility uses three Rentech Type-D water tube boilers and three night time preservation boilers. The California Energy Resources Conservation and Development Commission approved for each a stack "130 feet (40 m) high and 60 inches (1.5 m) in diameter" and consumption of 242,500 cu ft/h (6,870 m3/h) of fuel.
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