Solar automobile racing

DEFINITION: Competitions in which drivers travel specified distances in vehicles powered by the sun’s energy

Races featuring solar automobiles demonstrate the potential of solar energy to provide sustainable transportation. Solar car races motivate engineers and scientists to refine vehicle and energy technologies utilizing solar power. Several manufacturers have appropriated innovative features and designs developed for those competitions to use in the vehicles they produce.

In 1982 Hans Tholstrup departed from Sydney, Australia, in a solar-energy-powered automobile. He traveled west, covering 4,052 kilometers (2,518 miles) in twenty days, averaging 23 kilometers (14.3 miles) per hour, to reach Perth. Inspired by that experience, Tholstrup envisioned a transcontinental competition in Australia to promote solar vehicle technology research. The detrimental impact of fossil-fuel emissions on the concerned Tholstrup, who emphasized that solar cars do not produce such damaging emissions. He established the World Solar Challenge (WSC), with the debut race occurring in 1987.

The first WSC started in Darwin in northern Australia, following the Stuart Highway 3,000 kilometers (1,864 miles) south to Adelaide. Tholstrup stressed that participants’ vehicles had to rely completely on solar power. According to the rules, the cars could race from 8:00 A.M.to 5:00 P.M.daily, and the first vehicle to reach the finish line would be named the winner. The drivers endured extremely hot temperatures, windstorms, and other difficulties. A solar automobile developed by General Motors, the Sunraycer, won the race, averaging 66.9 kilometers per hour (41.6 miles per hour).

Solar cars raced in the WSC in 1990, 1993, and 1996 along the same route, before the South Australian government purchased the competition from Tholstrup; since that time the race has been held every two years. The WSC remains the most important solar automobile racing contest in the world, but solar automobile racing has gone on to attract diverse participants and sponsors, and other races are held worldwide, including the North American Solar Challenge. In 2009 the WSC became part of the Global Green Challenge, an event that encompasses both the WSC competition and the Eco Challenge, a competition for “environmentally friendly production and experimental vehicles.”

A solar car is typically constructed with light carbon fiber composite materials, such as Kevlar, that form a wide surface area, approximately 6 square meters (65 square feet), on which are mounted solar cells, typically made from silicon, which convert solar energy into electricity; this energy is stored in lithium batteries, which power electric motors that power the vehicle. Competitors in solar races strive to reduce the weight and drag of their vehicles and improve the vehicles’ aerodynamics. Many invest in relatively costly materials, such as gallium arsenide, for their solar cells to maximize the amount of solar energy converted into electricity; for example, solar cells made from gallium arsenide can convert 26 percent of solar energy into electricity, compared with 20 percent for solar cells made from silicon. Solar cars can move very quickly; racers in the WSC often exceed South Australia’s speed limit of 110 kilometers (68 miles) per hour.

The strategies used by solar car racing teams include computer modeling to simulate races. Some teams use weather balloons to assess cloudiness on race routes. Racers often position mirrors on their solar cars to direct sunlight to the solar cells. Competitors also place microprocessors on batteries and utilize wireless communications between the solar cars and their support teams so the teams can remotely set the solar cars’ speeds after interpreting data.

Many automobile makers have been impressed by the technologies developed by solar automobile racing competitors, some of which may be employed to enhance the energy efficiency and reduce the carbon emissions of other vehicles. As a result of advances made in solar automobile racing, for example, some manufacturers have incorporated tires with reduced rolling resistance, batteries that store more energy for greater durations, and improved aerodynamics in mainstream vehicles.

Bibliography

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