Energy Central, Renewables Biz : December 15 2009
By Bill Opalka
Any day now, innovative concentrating solar power units will start feeding electricity onto the grid in Arizona. The units are part of the Salt River Project in Maricopa County, a 1.5-megawatt demonstration plant that will be officially dedicated sometime next month. And that’s just a start. In less than a year, ground will be broken on two projects using the SunCatcher CSP technology, slated to be the largest solar electric generation plants in the U.S., totaling at least 1,600 megawatts. These projects, and a third, have long-term power purchase agreements in hand, and are being developed by Tessera Solar using technology developed by its sister company, Stirling Energy Systems.
“Maricopa is a 60-dish project and is the first large-volume system,” says Bob Lukefahr, Tessera’s CEO, the former CEO of BP Wind. Prior versions of the technology date to the first energy crisis in the 1970s and were developed by Ford Motor Company. In the ensuing years, the technology was owned and refined by the automaker, aerospace companies and eventually investors who acquired it in the 1990s and created Stirling Energy Systems. That company developed the technology over the next few years along with the Department of Energy and the Sandia National Laboratory in New Mexico, where the signature product, the SunCatcher was born. “We are using the original concepts which have been continually developed over a long period of time,” Lukefahr says.
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 SunCatcher can generate 250 kilowatts. And Lukefahr says the company can scale up rapidly, employing some of the same skill sets and techniques from it automotive industry forebears. That’s something Stirling is now prepared to do.
The financial shot-in-the-arm came in early 2008 when the company attracted an Irish energy company with a pocketful of cash looking to invest in the U.S. market. NTR plc had just sold its Airtricity wind power unit that included a portfolio of projects in the U.S. in two transactions that grossed $2.7 billion. It was now looking to re-establish in North America with renewable energy, including solar, and invested $100 million in SES.
NTR determined there were natural divisions between a technology development company and a project developer, as just about the entire utility industry had concluded over the decades. Hence, Tessera Solar was born in early 2009, with international and North American divisions to build projects employing the Stirling technology.
Tessera, based in Scottsdale, Arizona, has PPAs to build the 750-megawatt Imperial Valley, California project for San Diego Gas & Electric, using 30,000 systems; Calico, San Bernardino County, California project for Southern California Edison with 34,000 SunCatchers; and the 27-megawatt Western Ranch Solar, in Texas for CPS Energy, with 1,080 SunCatcher systems. Lukefahr says at an expected cost of lower than $3 million a megawatt, he’s expecting SunCatchers to eventually being cost-competitive with other generation resources – and ever more prolific.