Solar Cars Still in the Dark

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As opposed to the simpler photovoltaic cells you might find on the roof of a house or on a solar-powered calculator, which make use of about 15% of the energy available in sunlight, these "multi-junction" cells are about 27% efficient and cost about 100 times more.

The photovoltaic industry, initially fueled by space applications (such as powering communications satellites), has seen rapid growth in recent years because of an increase in demand for renewable energies in the commercial marketplace. According to Paul Maycock, industry consultant and president of Williamsburg (Va.)-based Photovoltaic Energy Systems, the sector has seen 40% compounded growth over the past seven years to reach around $15 billion in 2006. Currently about 15% of that market is in consumer products, such as grid-connected rooftop panels. It may grow by as much as 40% compounded over the next 20 years.

Solar cell makers see autos as a possibility but aren't factoring them into their projections for the foreseeable future. "We're always looking at new markets," says David Danzilio, general manager of Emcore's photovoltaic division. "Nobody from the automotive industry has approached us. Our products will be quite suitable to that application when the time comes."

Others are more skeptical. "I don't think there will ever be [a production solar-powered car] that's very feasible," says Tom Carroll, a recent graduate of UofM and the current business director for its Solar Car Team. "If you look at our car, the weight is around 600 pounds, it generates about two horsepower, and it has one driver who's not exactly the most comfortable."

Unplug and Go

And perhaps advances toward plug-in electric cars and residential solar panels will supplant the need for a solar-powered car altogether. Imagine, for example, a world where every garage has a roof lined with solar panels, and everyone plugs their car in when they get home. When they get to work, they plug their car into the solar chargers in the company parking lot. If these advances come to fruition, why cart around expensive solar panels all day and deal with their slower speeds and shorter range?

In January of next year, French sports carmaker Automobiles Venturi will be the first company to launch a production hybrid solar-electric car. The Astrolab is a light, two-person car with 21% efficient solar cells. It can go up to about 75 mph and has a range of 68 miles. While a surprising pioneer, the Astrolab shows the limitations of solar power. It will cost around $125,000—the cost of a high-end sports car or ultra-luxury sedan—but looks more like a go-kart than a car.

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MacMillan is a reporter at BusinessWeek.com in New York.