CLEAN ENERGY Solar farms shine new light on cheap power

Engineers also are working on technology to make a field of solar dishes work in concert.
SCRIPPS HOWARD
Outside a remote New Mexico office with a "Watch for Snakes" sign taped to the door is a potential helping hand for the 21st century energy blues.
The office, part of Sandia National Laboratories' solar research facility, is working with a private company to develop solar dish farms. The farms -- with upwards of 20,000 dishes each -- could produce enough power to compete with expensive peaking power stations, saving customers money in power-use-heavy seasons, said Chuck Andraka, a Sandia engineer.
Peaking stations use costly natural gas to meet power demands when normal coal and nuclear plants don't provide enough energy. Solar farms -- once the technology is fully developed -- could do the same job for less, he said.
"Peaking power with natural gas can cost from 10 cents to 30 cents or more per kilowatt-hour," Andraka said. "We can't compete with coal or nuclear, which are in the 3 cents to 5 cents range, but we think we can make solar farms that produce energy at about 6 cents per kilowatt-hour, which could make it highly competitive in the peaking market."
Complex operation
Operating a single dish is not a problem, but synchronizing 20,000 of them and making it economical? That's complex. That's why Sandia got involved, Andraka said.
"Costs for solar technology are pretty expensive right now, but if we can build production line automation to make dishes and use less expensive components, those costs will come down," Andraka said. "There are a lot of interesting engineering problems involved."
Production line and materials technologies have improved dramatically over the past 20 years, and applying those to the dish technology, which was developed in the 1980s, will help save production costs, he said.
Sandia engineers also are working on techniques and computer programs to make a field of solar dishes work in concert, which is not as easy as it might sound, Andraka said.
"If 20,000 of those went on at the same time, you'd damage the power grid," he said.
Starting them staggered one minute apart wouldn't work either. It would be dark before the last ones were up and running, Andraka said.
"What we need to do is find a way to start these things up a millisecond apart, so they don't hurt the power grid but they come up in a timely fashion," he said.
Out in the snake-saturated nether regions of Sandia, the engineers have set up a small test field of six dishes to work out the bugs on a small scale before they become major problems.
Readiness
Stirling Energy Systems Inc. thinks it will be ready to start building its first solar farms in the next two to three years, said Bob Liden, the company's executive vice president and general manager.
"This is the perfect type of electricity generation for the Southwest," Liden said. "It's a renewable resource, it's pollution free, and the maintenance of a solar farm is minimal."
Andraka is more cautious, saying it will probably be about three years before construction of a 20,000-dish solar field begins.