For Immediate Release: September 28, 2012
Media Contact: Sandy Louey - 916-654-4989


Preliminary Staff Assessment Released for the
Rio Mesa Solar Electric Generating Facility

SACRAMENTO - The California Energy Commission staff today released its preliminary analysis of the proposed Rio Mesa Solar Electric Generating Facility project.

In the preliminary staff assessment (PSA), Commission staff concluded, in all but six technical sections, with the implementation of recommended mitigation measures described in the conditions of certification, the proposed 500-megawatt (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 with either a significant, unmitigated impact, LORS non-compliance, or outstanding issues that need to be resolved through additional data, further discussion and/or analysis are: geology and paleontology, soil and surface water, traffic and transportation, transmission system engineering, water supply and visual resources.

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 October 15.

The PSA is available at:

The PSA serves as the Commission staff's initial evaluation of the environmental, engineering, public health and safety impacts of the proposed facility. The PSA is not a decision nor does it contain final findings of the Commission related to the environmental impacts or the project's compliance with local, state and federal legal requirements.

After at least one public workshop and a public comment period on the PSA, Commission staff will release a final staff assessment (FSA). The FSA will serve as staff's testimony at evidentiary hearings conducted by the committee of two commissioners reviewing the proposed project. The committee will issue a proposed decision based on evidence presented at the hearings. The proposed decision will be presented to the full Commission for a final decision.

BrightSource Energy, Inc. is the applicant for the Rio Mesa project. 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 Rio Mesa project would be located on the Palo Verde Mesa in Riverside County, about 13 miles southwest of Blythe. The proposed 3,805-acre site would be located on land leased from the Metropolitan Water District of Southern California. This site would include the two proposed power plants, heliostat fields, and support facilities. Additional land area required to accommodate the project gen-tie line, emergency and construction electrical power supply line, and primary access road would be located on federal land administered by the U.S. Bureau of Land Management.

The project had originally been submitted to the Commission in October 2011 as a 750-MW project. The site was proposed on approximately 5,750 acres located partially on leased land and partially on public land administered by the BLM.

In July 2012, BrightSource filed an amended application for certification that removed the northernmost 250-MW power plant that would have been on BLM land. 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 estimated capital construction cost for the 500-MW Rio Mesa project is about $2 billion. If the project is approved, construction of the facility, from site preparation and grading to commercial operation, would take about 30 months. 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.

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

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The California Energy Commission is the state's primary energy policy and planning agency. Created by the Legislature in 1974 and located in Sacramento, six basic responsibilities guide the Energy Commission as it sets state energy policy: forecasting future energy needs; licensing thermal power plants 50 megawatts or larger; promoting energy efficiency and conservation by setting the state's appliance and building efficiency standards; supporting public interest energy research that advances energy science and technology through research, development, and demonstration programs; developing renewable energy resources and alternative renewable energy technologies for buildings, industry and transportation; planning for and directing state response to energy emergencies.