Rio Mesa Solar Electric Generating Facility

The Rio Mesa Solar Electric Generating Facility was a proposed 500 MW solar thermal power project in Riverside County, California. The developers for the project were subsidiaries of BrightSource Energy, Inc. The plant was expected to cost about $2 billion.

The plant was to comprise two solar power towers, each with a generating capacity of 250 MW. About 170,000 heliostats would have reflected sunlight to the receivers mounted on top of the 750 ft towers. The project was scaled down from 750 MW to 500 MW in May 2012, for which it has a power purchase agreement (PPA) with Southern California Edison (SCE).

In December 2011, the California Energy Commission (CEC) accepted the application for certification for the Rio Mesa SEGF. In October 2012, Rio Mesa received preliminary approval from the CEC; final approval was needed by June 2013 to fulfill its PPA. However, the discovery of a large deposit of Pleistocene fossils underlying part of the project's area delayed approval or construction. In January 2013, BrightSource suspended the Rio Mesa project; the project was formally cancelled in July 2013.