Cheaper Solar Thermal Power

Stirling Energy Systems (SES), based in Phoenix, has decreased the complexity and cost of its technology for converting the heat in sunlight into electricity, allowing for high-volume production. It will begin building very large solar-power plants using its equipment as soon as next year.

Sun catchers: This is the latest design of a system for focusing sunlight on a Stirling engine to generate electricity. Credit: Sandia National Laboratories/Randy Montoya

The company is currently building a 1.5-megawatt, 60-unit demonstration plant that will use the company's latest design. Stirling expects to finish that project by the end of the year. It also has contracts with two California utilities to supply a total of 800 megawatts of solar power in Southern California. The first of the plants that will supply this power could be built starting the middle of next year, pending government permits and loan guarantees from the U.S. Department of Energy (DOE).

The projects are part of a resurgence in what's known as solar thermal power. Various solar thermal technologies were developed starting in the 1970s, but a breakdown in government funding and incentives caused them to stall before they reached a scale of production large enough to drive down costs and allow them to compete with conventional sources of electricity. "It was a classic problem with solar. The market support to bring solar to high volume wasn't there," says Ian Simington, the chairman of SES and chief executive of the solar division of NTR, a company based in Dublin, Ireland, that bought a controlling share of SES last year.

Recent state mandates and incentives for renewable energy have led to a new push to commercialize the technology. There are over six gigawatts of concentrated solar power under contract in the southwestern United States right now, says Thomas Mancini, program manager for concentrated-solar-power technology at Sandia National Laboratory in Albuquerque, NM. That's equivalent to about six nuclear-power plants. BrightSource Energyhas contracts to provide 2.6 gigawatts of solar power with concentrated solar power (a previous version of this story cited only one of two 1.3 gigawatt contracts), and Solar Millenium has announced a project that would generate nearly one gigawatt of power. link...