Solar Cars Still in the Dark

Solar-powered cars may never be economically feasible, but the technology developed could still help reduce dependency on fossil fuels

by Douglas MacMillan

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On July 14 the students in University of Michigan's Solar Car Team unveiled the Continuum, a super-aerodynamic one-man racer that sports a shimmering armor of solar panels. The Continuum, UofM's ninth solar racer in 18 years, is a top contender in this October's Panasonic World Solar Challenge—a roughly 1,900-mile race from the northern to southern border of Australia. Compared with previous generations, this car looks less like something out of The Jetsons and more like something the average consumer might one day drive to work.

That's because Events South Australia, the division of the country's tourism commission that organizes the race, this year imposed new rules to encourage more practical, commercially feasible, sustainable vehicles. UofM and its competitors, 46 other corporate-sponsored universities and research labs, now must use some 25% fewer solar cells than years before, drivers must sit at a slightly more upright, 26-degree angle, and all cars must observe the country's 110 km/h speed limit (about 68 mph).

The Solar Race is On

While a production solar-powered car is still more an object of science-fiction wonder than a near-term reality, in recent years several solar-powered boats have hit the market (see BusinessWeek.com, 5/17/07, "New Light on Solar Energy"). Now staging its 20th biannual race, the World Solar Challenge has emerged in both renewable energy and automotive industries as the central catalyst of worldwide innovation aimed at this elusive goal. The North American Solar Challenge, another biannual race formerly sponsored by the U.S. Energy Dept., is chiefly an academic competition.

"The solar car competitions do drive technology forward, but in a more exploratory way rather than directly applicable technology to mass-produced automotive applications," says Dean Degazio, development engineer for hybrid vehicle integration at General Motors (GM). For years, GM has played a major role in the UofM team's cadre of backers, a list that also includes Ford (F), Netherlands-based diversified resources company BHP Billiton (BBL), and Michigan-based automotive technology maker Denso. "Advances in structures, power management, solar cell output, and ingenuity of design for low drag, low rolling resistance," says Degazio, make solar cars "very compelling projects in the context of an engineering curriculum."

The mass market certainly couldn't afford a car like the Continuum. Whereas in 1989, the team's first year of development, donations of cash and materials totaled less than $500,000, in 2005 they came to $1.8 million. For 2007's Continuum, the team raised upward of $2 million. For the first time, GM supplied the molds for the Continuum—a tax write-off of about $50,000. Ford will be supplying a wind tunnel model and will help train the team's drivers.

Costly Cells

By far the most expensive component of the Continuum is its high-efficiency photovoltaic solar cells, the silicon-based panels that convert the sun's rays into electricity. UofM spends about $500,000 on the high-end cells, which are made only by a handful of companies, such as Albuquerque (N.M.)-based Emcore (EMKR), and Sylmar (Calif.)-based Spectrolab, a subsidiary of Boeing (BA).