* Firm says 500 MW project suspended
* Regulators have said facility would impact environment
LOS ANGELES, April 3 (Reuters) - U.S. BrightSource Energy Inc has shelved a major solar power project in California, its second such move this year.
The solar plant developer said in a document filed with the California Energy Commission on Wednesday that it was suspending its application for permission to build the 500 megawatt Hidden Hills solar thermal power project until further notice.
It added in an emailed statement that it had agreed with Pacific Gas and Electric to terminate the utility's plan to purchase power from the plant due to "challenges associated with the project schedule and uncertainty around the timing of transmission upgrades".
Late last year, CEC staff said the Hidden Hills facility would have "significant" impact on the environment, adding that the use of photovoltaic solar panels "would be environmentally superior" to BrightSource's solar thermal technology.
BrightSource disputed those claims at recent hearings, and the CEC was expected to issue a final decision on the development later this year.
BrightSource, based in Oakland, California, said it would continue to evaluate the project, which was to be located in Inyo County near the Nevada border.
In January, BrightSource suspended its 500 MW Rio Mesa project in Riverside County, California, after multiple delays in the permitting process.
The company, which canceled a planned initial public offering last year, said Hidden Hills remains "a valuable site" but that it would focus on its 500 MW Palen project in the meantime.
In March, BrightSource said Spain's Abengoa would become a partner in that project, expected to begin construction at the end of 2013 and to come online in 2016. It is still waiting for regulatory approval.
BrightSource is more than 20 percent owned by French power equipment maker Alstom SA. Other investors include VantagePoint Capital Partners, DBL Investors, Goldman Sachs Inc , Chevron Technology Ventures and BP Ventures .