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Powering the Future
AUGUST 2005
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Powering the Future

By Michael Parfit
Photographs by Sarah Leen

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Solar electric systems catch energy directly from the sun—no fire, no emissions. Some labs and companies are trying out the grown-up version of a child's magnifying glass: giant mirrored bowls or troughs to concentrate the sun's rays, producing heat that can drive a generator. But for now, sun power mostly means solar cells.

The idea is simple: Sunlight falling on a layer of semiconductor jostles electrons, creating a current. Yet the cost of the cells, once astronomical, is still high. My modest system cost over $15,000, about $10 a watt of capacity, including batteries to store power for when the sun doesn't shine.

Like most things electronic, solar power has been getting cheaper. "Thirty years ago it was cost-effective on satellites," says Daniel Shugar, president of PowerLight Corporation, a fast-growing California company that has built solar installations for clients including Toyota and Target. "Today it can be cost-effective for powering houses and businesses," at least where utility power is expensive or unavailable. Tomorrow, he says, it will make sense for almost everyone.

Martin Roscheisen, CEO of a company called Nanosolar, sees that future in a set of red-topped vials, filled with tiny particles of semiconductor. "I put some of that on my finger, and it disappeared right into my skin," he says. He won't say exactly what the particles are, but the "nano" in the company name is a hint: They are less than a hundred nanometers across—about the size of a virus, and so small they slip right through skin.

Roscheisen believes those particles promise a low-cost way to create solar cells. Instead of making the cells from slabs of silicon, his company will paint the particles onto a foil-like material, where they will self-assemble to create a semiconductor surface. The result: a flexible solar-cell material 50 times thinner than today's solar panels. Roscheisen hopes to sell it in sheets, for about 50 cents a watt.

"Fifty cents a watt is kind of the holy grail," says David Pearce, president and CEO of Miasolé, one of many other companies working on "thin-film" solar cells. At that price solar could compete with utilities and might take off. If prices continued to drop, solar cells might change the whole idea of energy by making it cheap and easy for individuals to gather for themselves. That's what techies call a "disruptive technology."

"Automobiles were disruptive to the horse and buggy business," Dan Shugar says. "PCs were disruptive to the typewriter industry. We believe solar electric systems will be disruptive to the energy industry."

Yet price isn't the only hurdle solar faces. There are the small matters of clouds and darkness, which call for better ways of storing energy than the bulky lead-acid batteries in my system. But even if those hurdles are overcome, can solar really make the big energy we need?

With solar now providing less than one percent of the world's energy, that would take "a massive (but not insurmountable) scale-up," NYU's Hoffert and his colleagues said in an article in Science. At present levels of efficiency, it would take about 10,000 square miles (30,000 square kilometers) of solar panels—an area bigger than Vermont—to satisfy all of the United States' electricity needs. But the land requirement sounds more daunting than it is: Open country wouldn't have to be covered. All those panels could fit on less than a quarter of the roof and pavement space in cities and suburbs.


WIND: FEAST OR FAMINE

Wind, ultimately driven by sun-warmed air, is just another way of collecting solar energy, but it works on cloudy days. One afternoon I stood in a field near Denmark's west coast under a sky so dark and heavy it would have put my own solar panels into a coma. But right above me clean power was being cranked out by the megawatt. A blade longer than an airplane wing turned slowly in a strong south breeze. It was a wind turbine.

The turbine's lazy sweep was misleading. Each time one of the three 130-foot (40-meter) blades swung past, it hissed as it sliced the air. Tip speed can be well over 100 miles (160 kilometers) an hour. This single tower was capable of producing two megawatts, almost half the entire output of the Leipzig solar farm.

In Denmark, turning blades are always on the horizon, in small or large groups, like spokes of wheels rolling toward a strange new world. Denmark's total installed wind power is now more than 3,000 megawatts—about 20 percent of the nation's electrical needs. All over Europe generous incentives designed to reduce carbon emissions and wean economies from oil and coal have led to a wind boom. The continent leads the world in wind power, with almost 35,000 megawatts, equivalent to 35 large coal-fired power plants. North America, even though it has huge potential for wind energy, remains a distant second, with just over 7,000 megawatts. With the exception of hydroelectric power—which has been driving machines for centuries but has little room to grow in developed countries—wind is currently the biggest success story in renewable energy.

"When I started in 1987, I spent a lot of time sitting in farmers' houses until midnight talking to the neighbors, just selling one turbine," says Hans Buus. He's director of project development for a Danish energy company called Elsam. "I would not have been able to imagine the level it is today."

He means not only the number of turbines but also their sheer size. In Germany I saw a fiberglass-and-steel prototype that stands 600 feet (200 meters) tall, has blades 200 feet (60 meters) long, and can generate five megawatts. It's not just a monument to engineering but also an effort to overcome some new obstacles to wind power development.

One is aesthetic. England's Lake District is a spectacular landscape of bracken-clad hills and secluded valleys, mostly protected as a national park. But on a ridge just outside the park, though not outside the magnificence, 27 towers are planned, each as big as the two-megawatt machine in Denmark. Many locals are protesting. "This is a high-quality landscape," says one. "They shouldn't be putting those things in here."

Danes seem to like turbines more than the British, perhaps because many Danish turbines belong to cooperatives of local residents. It's harder to say "not in my backyard" if the thing in your backyard helps pay for your house. But environmental opposition is not the only trouble facing wind development. Across Europe many of the windiest sites are already occupied. So the five-megawatt German machine is designed to help take wind power away from the scenery and out to abundant new sites at sea.

Many coastlines have broad areas of shallow continental shelf where the wind blows more steadily than on land and where, as one wind expert puts it, "the seagulls don't vote." (Real voters, however, sometimes still object to the sight of towers on the horizon.) It costs more to build and maintain turbines offshore than on land, but an underwater foundation for a five-megawatt tower is cheaper per megawatt than a smaller foundation. Hence the German giant.


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