General Motors Sponsors a Solar-Powered Car Race

General Motors, the U.S. Department of Energy, and the Society of Automotive Engineers held a race for solar-powered cars in the United States to challenge college engineering students and to show the potential of solar energy and electric vehicles.

Summary of Event

In 1987, Hughes Aircraft, Hughes Aircraft Company an independently managed subsidiary of General Motors (GM), and AeroVironment, AeroVironment[Aerovironment] a company in which GM held stock, built a solar automobile called the Sunraycer Sunraycer (automobile) to compete in the 1,867-mile Pentex World Solar Challenge Pentex World Solar Challenge
World Solar Challenge in Australia. Howard G. Wilson, Paul B. MacCready, Chester R. Kyle, Kyle, Chester R. and their teams combined light weight, aerodynamics, energy efficiency, and reliability in the automobile’s design to produce the capacity for an average speed of 41.6 miles per hour. The Sunraycer won the race. Energy;solar
Automobiles;solar-powered[solar powered]
General Motors
GM Sunrayce USA
American Solar Challenge
Solar power;automobiles
[kw]General Motors Sponsors a Solar-Powered Car Race (July 9-19, 1990)
[kw]Solar-Powered Car Race, General Motors Sponsors a (July 9-19, 1990)
[kw]Car Race, General Motors Sponsors a Solar-Powered (July 9-19, 1990)
Automobiles;solar-powered[solar powered]
General Motors
GM Sunrayce USA
American Solar Challenge
Solar power;automobiles
[g]North America;July 9-19, 1990: General Motors Sponsors a Solar-Powered Car Race[07800]
[g]United States;July 9-19, 1990: General Motors Sponsors a Solar-Powered Car Race[07800]
[c]Energy;July 9-19, 1990: General Motors Sponsors a Solar-Powered Car Race[07800]
[c]Engineering;July 9-19, 1990: General Motors Sponsors a Solar-Powered Car Race[07800]
[c]Transportation;July 9-19, 1990: General Motors Sponsors a Solar-Powered Car Race[07800]
Wilson, Howard G.
King, Richard
MacCready, Paul B.
Williams, Jerry

GM could not hope to surpass the tremendous success of the Sunraycer by building another automobile for the next Solar Challenge. Instead, project manager Wilson suggested to GM that U.S. engineering colleges be invited to compete against one another. GM leaders Bob Stempel Stempel, Bob and Donald J. Atwood Atwood, Donald J. recognized the educational potential of solar automobiles, and the idea met with almost instant approval from GM. Other potential backers were contacted. It made sense, according to Richard King of the U.S. Department of Energy Department of Energy, U.S. (DOE), to encourage future engineers and to stir public interest with a collegiate competition. Accordingly, the DOE and the Society of Automotive Engineers Society of Automotive Engineers (SAE) joined GM in sponsoring the first collegiate solar automobile competition. The race was named for GM’s solar racer: GM Sunrayce USA.

In December, 1988, the three sponsors invited more than one thousand North American colleges and universities offering technology and engineering programs to enter the competition to design and build a solar-powered vehicle. One hundred fifteen colleges responded, and sixty-one colleges completed designs. In April, 1989, twenty-nine entries were selected from U.S. schools, two from Canadian schools, and one from a school in Puerto Rico. The race was the largest such event held up to that time in the United States.

The rules for the race followed those for the 1990 Australian World Solar Challenge. Maximum vehicle dimensions were 6 meters (19.7 feet) long by 2 meters (6.6 feet) wide by 1.6 meters (5.3 feet) high. Minimum height was 1 meter (3.3 feet). Sunlight was to be the only source of power for the vehicles, and battery storage capacity was limited to five kilowatt-hours. Charging from the automobile’s solar array was allowed while the automobile was running the race and for the period two hours before and after each day’s racing.

The University of Michigan’s Sunrunner, which won the inaugural General Motors Sunrayce USA in 1990.

(Jim West)

On one-person vehicles, the solar panels could be up to 4 meters long (13.1 feet) by 2 meters wide (6.6 feet) and no more than 1.6 meters high (5.3 feet), or about 8 square meters. Two-person automobiles could be entirely covered with cells. Nevertheless, the entrants were faced with running their cars on less than 1,500 watts, or the power of a hair dryer. Minnesota’s Mankato State, for example, found that speeds exceeding twenty-five miles per hour caused energy output to exceed solar energy collection.

Driver compartments were to be enclosed to protect drivers and to ensure that no human power could aid a vehicle’s operation. Drivers would be warm and cramped; students would take turns driving to avoid heat exhaustion. Lead weights equalized drivers’ weights at 175 pounds minimum. Seat belts, horn, turn signals, taillights, and rear vision system were required.

Beyond these requirements, the focus was on dependability, stability, solar energy collection, storage in batteries, weight reduction, and aerodynamic design. Students were responsible for the design and assembly of every element of their automobiles. Those on the University of Michigan team, for example, voted on everything about their vehicle, even its door color.

Building a solar vehicle from scratch is costly. As an incentive, GM gave each school $5,000, and the DOE added $2,000. Each school had to raise the rest of its budget. The University of Michigan successfully put a team of business students in charge of fund-raising for the project. The schools spent between $30,000 and nearly $1 million to create their solar cars. Furthermore, student time demands ran high. As the race drew near, many teams worked around the clock, seven days a week, to finish their automobiles.

When the entrants from the thirty-two competing colleges and universities brought their completed vehicles to the starting point at EPCOT Center in Orlando, Florida, on July 9, 1990, excitement ran high. The teams saw the work of the other schools for the first time. Many had borrowed ideas from the Sunraycer, but others were more adventurous. Western Washington’s vehicle looked like the front of a small airplane. The aerodynamic Sunshine Special, Sunshine Special (automobile) designed by the Florida Institute of Technology, was so low to the ground that the supine driver had to look over his toes to see the road. The automobile even had extra solar cells under the chassis to catch sunlight reflected off the road.

The course followed an eleven-day, 1,625-mile back-road route from Lake Buena Vista, Florida, to the GM Technical Center at Warren, Michigan. The vehicles were timed as they attempted to reach set distances each day, and time bonuses and penalties were awarded. The teams’ fortunes varied, depending in large part on communication and teamwork. The competing teams tended to help one another, but sometimes the unexpected happened.

The University of Waterloo’s vehicle was in seventeenth place when a local driver in a truck attempted to pass and take a photograph of the unusual vehicle. An oncoming automobile caused all three vehicles to collide, and Waterloo’s Midnight Sun Midnight Sun (automobile) left the road looking like a flying saucer. No one was injured, but the Waterloo car was out of the race.

In the end, the University of Michigan’s 440-pound Sunrunner Sunrunner (automobile) finished first with a time of seventy-two hours, fifty minutes. Professor Bill Ribbens Ribbens, Bill was the team’s adviser. Susan Fancy Fancy, Susan was the team captain, and Paula Finnegan, Finnegan, Paula David Noles, Noles, David and Andrew Swiecki Swiecki, Andrew were drivers. Their single-person automobile featured aerospace silicon cells and silver-zinc batteries. Western Washington’s two-person car came in second, and the University of Maryland’s entry was third. As part of the package, GM sponsored the three automobiles to run in the 1990 World Solar Challenge, a repeat of the race the original Sunraycer had won in 1987.

A second Sunrayce event in 1993 followed a route from Arlington, Texas, to Apple Valley, Minnesota, and in 1995 the route was from Indianapolis to Golden, Colorado. Subsequent races in the series have taken place every two years. The name of the event changed to American Solar Challenge in 2001 and then to North American Solar Challenge North American Solar Challenge in 2005. During the same period, races involving “hybrid” vehicles—vehicles with two power sources, such as an electrical generator and an engine driven by propane, gasoline, or other fuel—began to be sponsored by the SAE, the Ford Motor Company, and Saturn.


The original Sunrayce drew large crowds. People were eager to see if automobiles that were powered by electricity could be more exciting than golf carts, and the idea of using the sun directly was intriguing. Students operating the vehicles were surprised at the public’s enthusiasm and felt like celebrities. Grocery stores along the race route sometimes refused payment from race participants, and even some repairs on the solar automobiles were done without charge.

Clearly, automobile manufacturers viewed the race as a window to the future, knowing that they must understand the market as they work to develop vehicles that are friendlier to the environment. Patrick Summers Summers, Patrick of the DOE noted that Sunrayce was a moving advertisement that automobiles do not have to be powered by gasoline.

Enthusiasm for the engineering project continued at the various schools that competed even after the race was over. The 1991 summer issue of the SAE newsletter, Student Action in Engineering, reported that nearly all the Sunrayce schools displayed their vehicles at fairs, career days, automobile shows, and hundreds of regional events. Members of the team from Mankato State University of Minnesota drove their Northern Light Northern Light (automobile) to the top of Pikes Peak in Colorado and gained a place in The Guinness Book of World Records. Arizona State University competed in the ASHI Solar Car Rally in Japan, where it earned the technology award.

At Auburn University, two students wrote their master’s theses on automobile elements. Dartmouth, Worcester Polytech, and Drexel began building new solar automobiles for the 1991 American Tour de Sol. More than 100,000 people saw Iowa State’s vehicle. The University of Ottawa presented a paper on solar vehicles at a conference on electric automobiles in Hong Kong and then displayed its automobile in Korea. Waterloo of Canada displayed its vehicle at the Toronto Science Center for three years and made plans for a natural gas-electric hybrid. Rose-Hulman Institute of Technology added a new motor. Stark Technical and Dartmouth reported the establishment of student solar automobile clubs. The hope that participation in the Sunrayce would stimulate the imaginations and energies of U.S. engineering students was clearly met.

College instructors and students saw the contest as an opportunity to build their programs by applying engineering and management principles to a real situation. GM is only one of many U.S. companies that have voiced concern that U.S. industry and competitiveness are being impaired by a lack of qualified engineering graduates. Events such as Sunrayce stimulate interest in technical education and careers. Realizing this, participating colleges have proudly featured their automobiles in recruitment brochures and videos.

The students who participated in the first Sunrayce recognized it as an extraordinary, life-changing experience. The intensity of the engineering process—how such a project is organized and how results are analyzed in terms of performance—introduced the students to real-life situations faced by engineers.

Richard King, the director of Sunrayce, pointed out that building solar-powered automobiles serves as a research and development test bed for all kinds of vehicles. Research and development under severe power limitations leads to the development of improved efficiency in any type of transportation. Howard Wilson agreed that much can be accomplished through this approach. The development of commercial electric and hybrid vehicles owes much to the lessons provided by competitions such as Sunrayce. A whole new sector of the automobile industry was created as the development of environmentally friendly vehicles proved increasingly feasible. Markets for such vehicles, particularly hybrids, grew substantially as the prices of these vehicles became more competitive and rising gasoline prices made them increasingly attractive to operate. Energy;solar
Automobiles;solar-powered[solar powered]
General Motors
GM Sunrayce USA
American Solar Challenge
Solar power;automobiles

Further Reading

  • Hampson, Bruce. “Making an Impact on the Electric Car Market: General Motors’ High-Tech EV Hits the Streets.” Electric Car 1 (Winter, 1994): 10-15. Details the development of GM’s electric automobile and its marketing strategy. States that GM’s interest in electric vehicles was reawakened by the success of the GM Sunraycer in the first Solar Challenge in Australia.
  • Nadel, Brian. “Sun Racers.” Popular Science 237 (August, 1990): 49-53, 88. Shows how the various college teams planned and built their vehicles to compete in the GM Sunrayce USA. Offers many details about the various automobiles.
  • Thacher, Eric F. A Solar Car Primer. New York: Nova Science, 2003. Presents comprehensive discussion of all aspects of the design and manufacture of the type of solar cars that take part in the Sunrayce competitions. Includes detailed appendixes and index.
  • Wilson, Howard G., Paul B. MacCready, and Chester R. Kyle. “Lessons of Sunraycer.” Scientific American 260 (March, 1989): 90-97. Excellent article points out the problems involved in building electric vehicles. Wilson saw the project as a way to show how Hughes Aircraft and GM could work together. Sunraycer made people think about practical alternatives to gasoline-driven vehicles and caused GM to think about sponsoring its own race.
  • Zygmont, Jeffrey. “Wheels: Here Comes the Sungo.” Omni 16 (May, 1994): 20. Describes the experience of riding in a solar automobile and points out the problems of building solar automobiles that can meet U.S. highway safety standards. Notes that the challenges in building these vehicles stem from the weight restrictions attributable to energy constraints.

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