Which Concentrating Solar Power Technologies will Prevail?

More large solar projects have been approved by the federal government on public lands in the West. One result, assuming they are all built, will be a contemporaneous test of how each concentrating solar power (CSP) technology performs.

“Projects from each of the main Concentrated Solar Power technologies have been backed, so the market really hasn’t picked a winner yet,” said Fred Morse, a senior advisor for Abengoa Solar and also the head of the CSP division for the Solar Energy Industries Association.

The federal Bureau of Land Management (BLM) signed off on six projects on public lands so far, five Concentrated Solar Power and one photovoltaic.

Just this week, the U.S. Interior Department, of which BLM is a part, approved a permit for what will be the world’s biggest solar power plant. The permit for a $6 billion, 1,000-megawatt solar project on federal land in the desert near Blythe, Calif. was issued to Solar Trust of America, a joint venture between Germany’s Solar Millennium AG and privately held Ferrostaal AG.

The Blythe Solar Power Project uses parabolic trough technology where rows of parabolic mirrors focus solar energy on collector tubes. The tubes carry heated oil to a boiler, which sends live steam to a turbine to produce electricity.

Last week, the Interior Department approved the Calico Solar Project. The project was proposed by Tessera Solar of Texas. The Calico Solar Project could produce over 663.5 megawatts of renewable energy in San Bernardino County, Calif.

In early October, Tessera Solar’s Imperial Valley Solar Project became one of the first utility scale projects to be approved by the BLM. The 709-megawatt project is in Imperial Valley, Calif.

Both projects will use the technology of Tessera’s sister company, Stirling Energy System’s SunCatcher technology. The Stirling system uses large concentrating mirrored parabolic dishes that resemble satellite dishes aligned in large arrays. Each dish-shaped surface collects and concentrates solar radiation onto a thermal receiver, positioned or aligned directly above its center, which absorbs the heat and transfers it to an engine generator, the company says.

A project that employs yet another technology is BrightSource Energy’s Ivanpah project in California, just a few miles from the Nevada border. A 370-megawatt solar thermal project uses thousands of mirrors to track the sun in two dimensions and reflect the sunlight to a boiler that sits atop a tower. The boiler creates superheated steam, which is then piped to a standard turbine where electricity is generated.

A modification of the parabolic trough technology, not in one of the federal sites, will be used in Arizona. Abengoa Solar’s 280 megawatt CPS plant will be installed about 70 miles southwest of Phoenix, near Gila Bend. Solana, with 250 MW nets of power output capacity, is based on parabolic trough technology and thermal storage using molten salts.

This story originally appeared in RenewablesBiz Daily and was written by its editor, Bill Opalca.  www.renewablesbiz.com/