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Big Solar Power Tower Projects Languishing in California Desert

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Rice, California, home of an unbuilt solar power plant | Photo: Chuck Coker/Flickr/Creative Commons License

Two large solar power projects that would use so-called "power-tower" technology to turn sunlight into electric power are still on hold in the California desert, according to documents published by a state agency in the last week.

Solar Reserve's 150-megawatt Rice Solar Energy Project, which was approved by the California Energy Commission in 2010, is languishing unbuilt on its site east of Joshua Tree National Park in Riverside County. So is the 500-megawatt Hidden Hills Solar Electric Generating System proposed for eastern Inyo County, which owner BrightSource Energy put on the back burner in April 2013 after a power purchase agreement with utility Pacific Gas and Electric fell apart.

The Rice project has even had its tortoise fencing and other equipment removed from the site, while Hidden Hills was pulled off the table before it had even been approved by the Commission. But owners of both projects are continuing to file progress reports as though the projects are still alive and viable.

Solar Reserve's Monthly Compliance Report for December 2014 for the Rice project, published on the Commission's website on January 30, can essentially be summed up as "we met all our obligations to the Commission during December, which was easy because since the site is open desert with no fencing or equipment, our only obligation was filing this report."

Meanwhile, an update on the suspended Hidden Hills project's status, filed by BrightSource on February 2 and published on the Commission's website the same day, says that BrightSource is working to line up new buyers for the project's power during the first months of 2015, and that the company hopes that process will "provide enhanced transparency pertaining to the permitting and construction schedule for the Hidden Hills CSP project."

In other words, BrightSource hopes to put the project back on the table with a new Power Purchase Agreement from a California utility, and will be able to suggest a timeline for approval and construction once that happens.

Hidden Hills' original agreement with Pacific Gas & Electric fell through in part due to mounting concerns over the project's environmental impact, as well as its effect on local cultural resources. Those concerns played out more fully in the analysis of the company's very similar Palen project, which BrightSource bowed out of in September.

That means that some of the work to analyze Hidden Hills' environmental impact, especially the issue of concentrated solar flux injuring wild birds who fly over the facility, has already been done on behalf of the Palen project.

But some of the issues at Hidden Hills will be unique to the project's site, in eastern Inyo County between the towns of Tecopa and Pahrump, Nevada. Water use is likely to be a key issue, and solar power tower plants do require a source of water to operate. BrightSource's smaller Ivanpah plant is allowed to use 100 acre-feet of the Ivanpah Valley's groundwater each year.

Environmentalists fear that drawing that much water (or more) for use at Hidden Hills from the aquifer beneath the site could affect the nearby Amargosa River, affecting sensitive species such as the federally endangered Amargosa vole. Nonetheless, Inyo County has targeted the area as potentially suitable for solar development in its draft Renewable Energy General Plan Amendment (that's a large PDF, so do be sure you want to click).

In his most recent inaugural address, Governor Jerry Brown pledged to raise the percentage of renewable energy powering the state's grid to 50 percent by 2030. Utility-scale solar developers like BrightSource and Solar Reserve can be expected to try to use Brown's pledge as leverage as they negotiate new power purchase agreements with the state's utilities. And those new agreements will help attract the investment capital needed to build the plants -- at least in theory.

Until that expanded Renewable Portfolio Standard becomes a reality, though, as solar investors continue to shy away from power tower plants, it looks as though these two solar projects will stay on life support for the time being.

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