Solar Trust of America, developer of the world’s largest solar electric system, the 1,000-megawatt Blythe Solar Project in California, is now looking to photovoltaics (PVs) for the first 500 megawatts of the project.

The project was originally planned as a concentrating solar plant (CSP) using parabolic troughs from Solar Trust parent Solar Millennium to superheat water into steam and generate electricity via turbines.

Solar Millennium, a German company, has developed its CSP trough systems in other countries, including the world’s largest such installations, the Andasol power plant in Spain. It’s also seeing the light of day in Egypt as part of a new solar-gas hybrid plant. But it’s the first time Solar Millennium has chosen to use photovoltaics in a project, according to Solar Trust spokesperson Edward Sullivan.

“This move underscores Solar Trust’s focus on maximizing the potential of our sites by deploying the right technology at the right time,” Uwe Schmidt, Solar Trust CEO, said in a press release. “We develop solar projects at the size and scope of the largest conventional power plants, and in doing so validate solar as a mainstream energy source.”

The company thinks that, at this point, photovoltaics are a more attractive option for developing the Blythe project. As supply of photovoltaic modules have gone up this year, their price has fallen, making PV more attractive than it was.

“Favorable conditions in the PV and commercial bank markets were the main drivers of the decision,” Sullivan said.

The change in technology for the first half of the project also will mean a change in how the project will be financed.

The Department of Energy offered $2.1 billion conditional commitment of a $2.1 billion loan to support construction of the first two, 250-megawatt CSP systems. But with the drastic change in the project, Solar Trust will seek funding from other sources.

“We will finance the project in the commercial bank market,” Sullivan said.

Changing to PV has another advantage, where previously the plant would come online in 250-megawatt blocks, it will now add the PV in phases, according to the release.

“The rollout plan will be determined in collaboration with our customer [i.e., Southern California Edison],” Sullivan said.

Because of the technology change, Solar Trust is also revising plans for the project.

“We are initiating the re-permitting process with the BLM [i.e., Bureau of Land Management] and other regulatory agencies,” Sullivan said.

Despite the change the footprint of the project will remain roughly the same, he said.

Initial construction on the Blythe solar project began this year.

“At this point, PV module suppliers haven’t been chosen yet. We are in active discussions with the leading suppliers in the industry,” Sullivan said.

Solar Trust still plans to build out the project to 1,000 megawatts, he said. It could still use parabolic troughs in later parts of the project.

Image courtesy of Solar Millennium of the Blythe plant under construction.