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. It is slated to close in 2026. 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 an initial synchronization test. The facility formally opened on February 13, 2014. At that time, it was the world's largest solar thermal power station.