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".KCET - Cities and Landmarks, the Etymology of the California Desert
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 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."World's Largest Solar Thermal Power Project at Ivanpah Achieves Commercial Operation" , NRG press release, February 13, 2014.
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 of public land near the California–Nevada border in the Southwestern United States. Initially it was planned with 440 MW gross on 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 press release Siemens to supply 123 MW steam turbine-generator set for solar thermal power plant in California Siemens also supplied instrumentation and control systems. The plants use BrightSource Energy's "Luz Power Tower 550" (LPT 550) technologyBrightSource & Bechtel Partner on 440-MW Ivanpah CSP Project Renewable Energy World, September 10, 2009. which heats the steam to 550 °C directly in the receivers." ", page 8 The plants have no storage.
Final approval for the project was granted in October 2010.BrightSource secures final approval for Ivanpah solar project , BusinessGreen.com staff, BusinessGreen, 08 Oct 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.Google cans concentrated solar power project Reve, 24 Nov 2011. Accessed: 25 Nov 2011.Google Renewable Energy Cheaper than Coal (RE<C) , Google. Accessed: 30 November 2011. $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 of natural gas, as previously approved, to .Approved petition Docketpublicenergy.ca.gov, (PDF) In 2014, the plant burned 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.Household energy Physics UCI. 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 " high and in diameter" and consumption of of fuel.
Economic impact BrightSource estimated that the Ivanpah facility would provide 1,000 jobs at the peak of construction, 86 permanent jobs, and total economic benefits of $3 billion. Elected San Bernardino County Supervisor Brad Mitzelfelt, who represents most of the California Mojave Desert, stated that the "project would create jobs for mostly Las Vegas and electricity for mostly San Francisco".
The project received a $1.6 billion loan guarantee from the United States Department of Energy. According to Synapse Energy Economics, the estimated construction cost for the facility of $5,561.00 per kW fell between that of coal and nuclear power plants, but this does not account for the less favorable capacity factor of solar power.
In November 2014, the facility's investors applied for a $539 million federal grant to finance their federal loan.
Performance Contracted power-delivery performance of 640 GWh/year from Units 1 and 3 and 336 GWh from Unit 2 was met by 2017, following sharply reduced production in the first few years of operation, particularly in the start-up year of 2014.
In November 2014, the Associated Press reported that the facility was producing only "about half of its expected annual output". The California Energy Commission issued a statement blaming this on "clouds, jet contrails and weather".Huge solar plant lags in early production , Associated Press, November 17, 2014 Performance improved in 2015 to about 650 GWh. However, NRG Energy said in its November quarterly report that Ivanpah would likely not meet its contractual obligations to provide power to PG&E during the year, raising the risk of default on its Power Purchase Agreement. PG&E had a contract to receive 640 GWh/year from Units 1 and 3, while SCE was supposed to receive 336 GWh from Unit 2, at a price of about $200/MWh (20¢/kWh). In March 2016, PG&E agreed not to declare the plant in default for at least four months in return for an undisclosed sum from the owners.
In June 2015, The Wall Street Journal reported, "15 months after starting up, the plant is producing just 40% of [its expected more than a million megawatt-hours of electricity each year], according to data from the U.S. Energy Department." Performance improved dramatically in the second year. CleanTechnica reported with respect to units 1 and 3 that "in 2015, PG&E customers received about 97% of Ivanpah's contracted electrons, which is a massive improvement over its first year".
By 2017, due to improvements, the plant was meeting the contract output requirements.
The steam plant was designed for 28.72% gross efficiency. The local irradiance near the area is about 7.4 kWh/m2/day (annual average) for a total solar energy flow in the visible spectrum of 2.717 MWh/m2 yearly.
One heliostat mirror is a reflecting surface, giving a total of per heliostat. The total plant heliostat reflecting surface results in 173,500 heliostats × 14.05 m2/heliostat = 2,437,144 m2. If the mirrors could always be perpendicular to Sun's ray, based on irradiance, the intercepted solar energy flow is 2.717 MWh/m2/year × 2,437,144 m2 = 6,621,720 MWh yearly.
May 2016 fire On May 19, 2016, a small fire was reported when misaligned mirrors reflected sunlight into a level of Unit 3 tower not designed to collect power, requiring the tower to shut down for repairs. As another of the three power-generating units was already offline for scheduled maintenance, the plant was left with only one third of its installation functional. Unit 3 resumed operation on June 8, 2016. All three units were back in operation by June 20, 2016. Solar thermal electricity production in California peaked at 703 MW on that day, up from 452 MW on June 7 when two units were offline.
Awards In August 2014, Ivanpah was given the "Plant of the Year" award by Power magazine. In February 2012, Ivanpah was named the CSP (Concentrating Solar Power) Project of the Year by Solar Power Generation USA.
Environmental impacts The Ivanpah installation was estimated, before operations started, to reduce carbon dioxide emissions by more than 400,000 tons annually. It was designed to minimize impacts on the natural environment compared to some photovoltaic solar facilities because the use of heliostats does not require as much grading of the land. The project was built on ecologically intact desert habitat. The facility was fenced off to keep out some terrestrial wildlife. However, birds faced the risk of collision with the heliostat mirrors or from burning in solar flux created by the mirror field.