Looking Into the Sun

If David Slawson is right about solar power, our days of oil dependency are numbered.

A relentlessly blue sky stretches over the sparse, nappy scrub and cacti in the desert several miles outside Albuquerque. Here, where there is otherwise little in any direction to suggest human existence, a lone, dusty road has led to a few unremarkable bungalows. Alongside them is a less unremarkable sight: a cluster of a half-dozen satellite-style dishes that look big enough to pick up programs from the outer planets. But these house-size dishes don't traffic in television. Their mirrored surfaces are aimed directly at the sun, twisting a few inches every six seconds to track it across the sky. Each dish focuses the equivalent of 10,000 suns' worth of heat on an eight-inch-wide maze of thin metal tubing perched above the dish's center.

Admiring one of the contraptions from below is David Slawson, a somewhat diminutive fellow in a leather jacket and slacks. Slawson may not cut an impressive figure, but he makes up for it with ambition. His dishes are self-contained, electricity-generating plants, fueled by the particles of energy hurled across 93 million miles of space by the nuclear reactor sitting at the center of our solar system -- that is, the sun. Slawson's quixotic plan: to cover large swaths of the earth's desert regions with emissionless solar farms. "A farm 100 miles by 100 miles would be enough to displace the fossil-fuel consumption of the U.S.," he says, sweeping his hand as if this vast installation already lies just off to the side. The dishes, he adds, will also help bring cheap electricity to the planet's 1.5 billion rural poor currently living without it.

"A solar farm 100 miles by 100 miles would be enough to displace the fossil-fuel consumption of the U.S."

Heady stuff, to be sure, and easy to dismiss. On the other hand, Slawson's company, Stirling Energy Systems, has some interesting credentials, including ownership of technology developed by McDonnell Douglas, Southern California Edison, and others at a cost of $400 million; $3 million in grants from the Department of Energy; a steady flow of angel investment that he says has averaged $2 million a year for nine years; a preliminary agreement to provide a major utility with up to $2.7 billion worth of electricity over 20 years; and another $1.3 billion deal on tap with another utility.

Slawson, 57, came to the unlikely role of would-be slayer of the world's monster oil habit through an even more unlikely route. He was running an alternative health care school in Portland, Oreg., in 1989 and had just moved to an apartment downtown. On his first night there, he opened his window before going to bed -- and got a faceful of vehicle exhaust. What, he wheezed to himself, is this world coming to? And more important, what was he, David Slawson, going to do about it? Charging across the street to a library first thing in the morning, he found his answer.

Solar energy seems like a no-brainer -- hey, free energy from the sky, what's not to like? -- but on closer inspection some thorny issues pop up. The biggest one is the "conversion efficiency" issue. Sunlight is energy, all right, but it needs to be converted to a form that can be used to run cars, heat homes, and display Leno. Electricity fills the bill, but a funny thing happens when you enlist sunlight to create electricity: Most of the energy flits away uselessly. The most common approach is to use sunlight to knock electrons out of a semiconducting material like silicon, creating an electric current. But the efficiency of even the very best photovoltaic systems, as the approach is called, tops out around 15% -- in other words, 85% of the sunlight's energy is wasted. Big, expensive solar panels in very sunny areas produce relatively little power, which winds up costing about 25 cents per kilowatt hour of electricity. (A kilowatt is about enough to power 14 75-watt bulbs.) Electricity from a conventional natural-gas-burning power station, by contrast, costs about seven cents per kilowatt hour.

Slawson's library raid turned up a book that detailed a different approach: a thermoelectric solar dish system developed by McDonnell Douglas (later absorbed into Boeing) with a Swedish firm called Kockums, technology that was later sold to and tested by Southern California Edison. Instead of using rays of sunlight to knock out electrons, the dish reflects and concentrates the rays in order to heat and thus expand a gas. That expansion is then put to work by a device called a Stirling engine to turn a conventional electric generator. The approach is nearly twice as efficient as most photovoltaic systems -- while doing away with semiconductors and other expensive materials.

These solar dishes are the world's great hope for renewable energy, says Slawson. Sure, there's hydropower, but there are only so many Niagara Falls. Drilling and other operating costs limit geothermal power, which taps heat energy trapped below ground. There's wind, but finding frequently windy sites where windmills don't spoil scenic vistas is a challenge -- and even then, the wind tends to die down during the summer and in the daytime, when demand is highest. And forget fuel cells -- they generate electricity, but the hydrogen they run on comes either from fossil fuels or by zapping water with electricity that still needs to come from somewhere else. "If you're an electric utility that wants renewable energy and you can get hold of a big plot of desert land, you're going to look at solar thermoelectric," says Michael Eckhart, a former General Electric and power industry executive who now heads the American Council On Renewable Energy in Washington, D.C.

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