photo: Tessera Solar
When it comes to renewable energy, Texas has been all about Big Wind. But this week the Lone Star State took on its first Big Solar project when San Antonio utility CPS Energy signed a 27-megawatt deal with Tessera Solar.
Houston-based Tessera is the solar farm developer for Stirling Energy Systems, which makes a Stirling solar dish. Resembling a giant mirrored satellite receiver, the 25-kilowatt solar dish focuses the sun’s rays on a Stirling engine, heating hydrogen gas to drive pistons that generate electricity. (Last year Irish green energy firm NTR pumped $100 million into Scottsdale, Ariz.-based Stirling Energy Systems and created Tessera to develop solar power plants using the Stirling dish, called the SunCatcher.
Stirling Energy Systems previously signed deals with Southern California Edison (EIX) and San Diego Gas & Electric (SRE) to supply up to 1,750 megawatts of electricity from some 70,000 solar dishes to be planted in the Mojave and Sonoran deserts.
Other solar developers privately have cast doubt on Stirling’s ability to make good on those contracts, arguing the SunCatcher is just too expensive and complex to compete against solar thermal technologies that rely on mirrors to heat liquids to create steam that drives electricity-generating turbines.
But earlier this week, Stirling unveiled the latest generation of the SunCatcher at Sandia National Laboratories in Albuquerque, N.M. The new SunCatcher has shed 5,000 pounds and its Stirling hydrogen engine contains 60% fewer parts than the previous version, according to the company.
The SunCatcher also uses a fraction of the water consumed by competing solar thermal technologies being developed by startups like BrightSource Energy and Ausra — no small deal in the desert. Tessera solar farms also can be built in modules, meaning that when a 1.5 megawatt pod of 60 SunCatchers is installed it can immediately begin generating electricity — and cash.
California utility PG&E also went modular Thursday when it signed a 92-megawatt deal with New Jersey’s NRG (NRG) for electricity to be generated by a Southern California solar power plant using eSolar’s technology. Google-backed (GOOG) eSolar’s builds its solar power tower plants in 46-megawatt modules. The power plants take up much less land than competing solar thermal technologies, thanks to eSolar’s use of sophisticated software to control small mirrors that are packed close together.
NRG earlier this month signed a deal to build a 92-megawatt eSolar-powered solar farm in New Mexico near the Texas border.
eSolar CEO Bill Gross says his solar farms will generate electricity cheaper than natural gas-fired power plants, a claim PG&E (PCG) appears to confirm in its submission of the deal to the regulators. (Thanks to Vote Solar for pointing to the document.)