Nearly 66% of the petroleum consumed in the United States is burned for transportation. In 1999, about sixty percent of the crude oil supply was imported from other countries.

The pollution resulting from burning vehicle fuels contributes to the greenhouse effect, acid rain, and smog. Vehicles powered by solar and other renewable energy resources are possible alternatives to conventional vehicles powered by internal combustion engines and fossil fuels.

Solar-powered vehicles (SPV’s), such as cars, boats, bicycles, and even airplanes, use solar energy to either power an electric motor directly, and/or use solar energy to charge a battery, which powers the motor. They use an array of solar photovoltaic (PV) cells (or modules made of cells) that convert sunlight into electricity. The electricity either goes directly to an electric motor powering the vehicle, or to a special storage battery. The PV array can be built (integrated) onto the vehicle body itself, or fixed on a building or a vehicle shelter to charge an electric vehicle (EV) battery when it is parked. Other types of renewable energy sources, such as wind energy or hydropower, can also produce electricity cleanly to charge EV batteries.

SPV’s that have a built-on PV array differ from conventional vehicles (and most EV’s) in size, weight, maximum speed, and cost. The practicality of these types of SPV’s is limited because solar cells only produce electricity when the sun is shining. Even then, a vehicle completely covered with solar cells receives only a small amount of solar energy each day, and converts an even smaller amount of that to useful energy. At present, most SPV’s with built-on PV arrays are only used as research, development, and educational tools, and/or to participate in the various SPV races held around the world.

Solar Car Designs

Perhaps the first, totally solar-powered car, the "Bluebird," was built by Ed Passerini, in 1977. Mr. Passerini has also built several other small, lightweight, and relatively low-cost (under $10,000) solar cars. At the other end of the spectrum, are solar cars equipped with advanced technology and built with the backing of large automobile manufacturers, including General Motors (GM), Ford, and Honda. Some solar cars use silver-zinc batteries, which have several advantages over traditional lead-acid batteries: they are lighter, are more efficient, and accept higher rates of charging. However, they are very expensive, and may only be charged and discharged (cycled) a few times before they become unusable and require recycling. While most developers use crystalline silicon cells in their designs, GM has used the higher efficiency, but more costly, gallium arsenide cells. GM’s Sunraycer has a 90 square-foot (8.4 square-meter[m2]) curved solar array integrated into the tear-dropped shaped body of the car. GM spent $8 million developing the Sunraycer.

John Mitchell Systems designed a SPV with a PV array integrated into two vertical air foils. These act as a sail to provide aerodynamic thrusts. In tests, the vehicle achieved 30 miles per hour (mph; or 48 kilometers per hour [kph]) using wind power alone. Ford Motor Co., and others, have designed tiltable arrays that track the sun.

Advances in lightweight structural materials have also contributed to improving solar car performance. The Sunraycer has an aluminum chassis and body made of two lightweight composite materials. While the car is 19.7 feet (6 meters [m]) long, 6.6 feet (2 m) wide, and 3.3 feet (1 m) high; the chassis weighs only 14 pounds (6.4 kilograms [kg]). The entire shell weighs less than 100 pounds (43.4 kg). The total weight of the vehicle, without the driver, is 390 pounds (177 kg).

Integration of PV Cells onto Conventional Cars

Kyocera Corporation developed a prototype solar-assisted electric commuter vehicle. It is a small, two-seat hatchback, and weighs about 1,200 pounds (544 kg). With its nickel-zinc batteries fully charged, the car has a top speed of 40 mph (64 kph) and a driving range of 70 miles (112 km). A 23 square feet (2.1 m2) PV array can extend this range up to 100 miles (160.9 km) on a sunny day.

Two auto manufacturers have introduced models with an optional PV panel incorporated into a sunroof. The PV panel runs a ventilation fan to cool the car when parked in the sun. Other potential uses of solar cells are for vehicle starting battery charge maintenance systems. PV battery charging arrays have been designed for rear spoilers, and a "solar wing," a feature similar to a rear spoiler that provides a downward force on the vehicle to help improve its traction on racetracks and highways.

PV EV Battery Charging

The Sacramento Municipal Utility District built a PV array that it uses to help charge several of the electric cars and trucks that it owns. The array also shelters the vehicles when they are being recharged. Edison EV, a private company, designs and builds these types of "charge ports" for EVs.

Solar Powered Bicycles, Boats, and Aircraft

The city of Palm Springs, California, has constructed 16 charging stations for electric bicycles around the city. The city’s police department and many commuters use the stations daily. The stations have lockers for electric bikes with an electrical outlet that is connected to a pole-mounted PV array. When parked and "plugged in," the array charges a bike’s battery.

In 1974, two brothers, Robert and Roland Boucher, flew the Sunrise I, an extremely light-weight, remote controlled, pilot-less aircraft powered by a PV array on the wings, to a height of 300 feet. The next year, their more advanced Sunrise II flew to 17,000 feet (5,000 meters). The US Air Force funded the development of these solar powered aircraft with the hopes of using them as spy planes. In 1980, the son of Paul MacCready, piloted a smaller, sun-powered version of the pedal-powered Gossamer Albatross (which Mr. MacCready had pedaled across the English Channel). With support from Dupont, MacReady built the Solar Challenger, and crossed the English Channel on July 21, 1981. It attained an average speed of 50 mph (80 kph), and at about 12,000 feet (3658 meters).

AeroVironment Inc. built the Pathfinder for the National Aeronautics and Space Administration (NASA) The Pathfinder is a remote controlled, 100 foot (30m) long "flying wing." It weighs less than 600 lbs (273 kg) and is almost completely covered by a thin-film PV array. Electricity from the array turns small motors that turn 8 propellers to move and steer the craft. It has flown to 80,000 feet (24,384 meters). It could be the precursor to solar powered aircraft that can stay aloft for months as alternatives to space-based remote sensing satellites.

Solar/battery powered boats are another type of SPV. PV (and wind energy) systems can charge batteries to run small electric lights and appliances, and even to run electric motors to move the boat itself.




1. Chassis - and seating

2. Mechanics - suspension, steering, brakes

3. Motor and drive train

4. Motor controller

5. Solar Array - usually part of body

6. Batteries or fuel cells

7. Electrical System - and instruments

8. Driver Controls - switches, lighting, etc

9. Bodywork - Screen, etc








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