July 27, 2009

Edison dismantles Daggett solar project

The central tower used in the Solar Two project in Daggett in the 1990s awaits dismantling on Wednesday. (Staff Photo by Jessica Cejnar)

Desert Dispatch

DAGGETT • Motorists traveling from Barstow to Needles may notice a change in scenery as they pass Daggett.

At a time when companies are developing solar energy sites all over the Mojave Desert, Southern California Edison and CST Environmental — a Brea-based demolition company — are busy dismantling one of the first projects to successfully store solar energy for use on cloudy days and at night.

Solar Two, built in Daggett in 1993, was a demonstration solar project that paved the way for other projects in Arizona and Spain to use the same technology on a larger scale, said Paul Phelan, manager of engineering in technical services for SCE’s Power Production Department.

But this year Phelan said SCE requested funds from the California Public Utilities Commission to decommission the project. The site wasn’t being used and break-ins were becoming a problem, Phelan said. Also, other parties, including SunRay Energy — a solar power company located in Malta — had expressed interest in possibly building another renewable energy facility near where Solar Two currently sits, Phelan said.

“Those are currently under evaluation by Edison’s Corporate Real Estate Department,” he said.

During its operation, Solar Two put 10 megawatts — enough to power about 6,500 houses — of electricity back into California’s power grid at the peak of summer, Phelan said. Almost 2,000 mirrors converged on a central tower where salt was heated until it became liquid. Phelan said the heated salt turned water into steam, which was used to run a turbine to generate power.

“They had two storage tanks that were insulated so they could store that salt in molten form until they needed it,” Phelan said. “They could run that again through the heating cylinder during dark hours or on cloudy days.”

The technology used in the Solar Two project didn’t exist except in peoples’ minds at that point, said Thomas Mancini, concentrating solar power program manager at Sandia National Laboratories, who worked with the project’s heliostat field. A consortium of 10 to 13 agencies, including Sandia Labs, SCE and the Department of Energy, were trying to demonstrate the project at a large enough level that the next step that could be taken would be to build commercial plants and operate them, Mancini said.

“What Solar Two did was provide experience levels with molten salt enabled projects in Spain, which is operating now,” he said, adding that Solar Two’s predecessor, Solar One, a water steam-driven plant operated at the Daggett site in the 1980s, was also the first project of its kind. “There are several power tower developers out there developing steam and molten salt. (They) build off the experience we had back in the ‘80s and ‘90s.”

SCE Spokesman Paul Klein, said the materials in the solar panels will be recycled. The glass will be disposed of as waste at a licensed landfill because the mirrored backing on the glass contains small amounts of lead, he said.

“Also, where possible, equipment — such as the turbine generator — will be sold as used equipment,” he said. “Remaining scrap metal will be sold for scrap value and recycled.”