California Energy Commission staff endorses Rio Mesa

The California Energy Commission (CEC) staff has given its early assessment of a large solar thermal plant and has recommended a series of measures to pass environmental and other regulations.

The Rio Mesa Solar Electric Generating Facility has been proposed by Oakland-based BrightSource Energy in Palo Verde Mesa in Riverside County, about 13 miles southwest of Blythe. In the preliminary staff assessment (PSA), Commission staff said, with exceptions in six technical areas, the proposed 500-MW solar thermal power project would comply with all applicable laws, ordinances, regulations, and standards (LORS) and that environmental impacts would be less than significant.

The six technical sections are: geology and paleontology, soil and surface water, traffic and transportation, transmission system engineering, water supply and visual resources.

If approved, the $2bn project would start construction in about a year. Construction would be staggered with the first solar plant scheduled to start the fourth quarter of 2013, while the second plant would begin the first quarter of 2014. The project would average 840 workers a month during construction, with a maximum of 2,188 at the peak. Up to 100 full-time employees would be needed when the project is operating, according to the applicant. Completion is expected in 2016.

The plant had originally been proposed a year ago as a 750-MW solar thermal plant that would have included one-third of it sited on federal lands managed by the Bureau of Land Management. BrightSource amended its application in July. The new project footprint removed the northernmost 250-MW section. The company made the change in response to issues raised during the early review process including cultural resources, biological resources, transmission corridor conflicts, and scheduling concerns from BLM.

The proposed project consists of two 250-MW solar plants. Each plant would have about 85,000 heliostats – elevated mirrors used to focus the sun’s rays on a solar receiver – that produces steam to generate electricity. The solar receiver is located atop a 750-foot tall power tower near the center of each solar field.

The proposed 3,805-acre site would be located on land leased from the Metropolitan Water District of Southern California. The company has agreed to sell power from Rio Mesa to Southern California Edison (SCE), a unit of California power company Edison International (NYSE: EIX).

The PSA is being published in two parts. The second part, which will consist of staff’s alternatives analysis and the biological resources, cultural resources, and land use sections, is scheduled to be filed by Oct.15.

After at least one public workshop and a public comment period on the PSA, Commission staff will release a final staff assessment (FSA).

More information on the Rio Mesa project can be found at: