It Works, but Can Anyone Afford It?
Giant 'spaceship' of mirrors uses sun to make electricity
| DAGGETT, CALIF.
From the air, the facility looks like a stadium-sized, alien spaceship made of mirrors.
From the ground, the 300-foot central tower appears to be an abandoned water tower until a flick of a switch makes its "receiver" top glow with a white-hot intensity that is not of this world.
The facility is Solar Two, and it is being touted by the US Energy Department and a consortium of western utilities as a giant leap for mankind in solar thermal power.
Others say it is a spectacular use of a misguided technology.
"Solar Two represents both a new source of clean power for California and neighboring states and a new source of export technology for America and for American workers," says John Bryson, chief executive officer of Southern California Edison, the electric utility that operates and manages the plant.
Not so, counters Chris Flavin, vice president for research at the Washington-based WorldWatch Institute. "It is sad that the US has poured millions into the wrong technology," he says, "without doing enough to create a viable marketplace for it to be used or sold."
Neither side disputes the big advance of molten salt technology that, for the first time, allows practical storage of solar energy. The storage capability means the facility can generate electricity after sunset.
After the specially developed, liquid salt compound is pumped to the top of this tower, it is heated to 1,050 degrees F by surrounding mirrors, 1,926 in all, which are computer-controlled for optimum angle to the sun. The superheated salt is then used to heat water and produce steam to drive a conventional turbine.
The $50 million site is technologically impressive, and as a demonstration project it will operate until 1998, producing enough electricity for 10,000 homes.
Because a major part of future solar use will depend on public attitudes, the DOE and consortium members recently produced quite a show to get a few dozen journalists out to this forbidding site in the scalding, 120-degree Mojave Desert. No less than a military color-uniform guard initiated a formal ceremony that included pledge of allegiance, performances by local school children, a TV personality as emcee, and participatory singing ("We love the sunshine, eternal sunshine" - to the tune of "You Are My Sunshine").
Over and over, officials here stated, clones of this model could be used in scores of similar sites worldwide. From Saudi Arabia to India to Mexico and South America, they could provide cheap solar energy to the earth's 2 billion residents who as yet have no electricity. This plant's energy costs, they said, are projected to range from 5 to 10 cents per kilowatt-hour, close to that of inexpensive natural gas.
But critics contend that such elaborate drumbeating is based on the faulty premise that developing countries need, or can afford, such larger-scale projects.
"The DOE has been pursuing this kind of large thermal project for 20 years now, but it is not viable on a grand scale," says Mr. Flavin, referring back to the 1970s when the US was rocked by Arab oil embargoes and began to seek alternative energy sources. He says the Solar Two program is the result of "wild-eyed" engineers who had access to government monies, $1.4 billion over 20 years by one estimate. (DOE's Chris Powers counters that the agency and its consortium share investment 50-50).
Flavin says solar power's future is not in large projects but cheaper, decentralized systems that rely on solar panels placed atop houses and huts from Brazil to Indonesia.
For now, US companies pull in $300 million a year in solar-equipment exports, mostly of smaller photovoltaic panels. Will this newer, larger technology light up the public imagination?
Scientists here hope to prove Solar Two is worth its salt.