Published: 29 March, 2000

Solar energy acts as fuel for solar enery cars

How do solar energy cars work?

A solar car gets the energy it needs to move from sunlight. If you look at the solar car below you can see that much of its surface looks black. This helps it to absorb the sunlight - black objects absorb most of the light that falls upon them.

Usually, black objects just get hot in the sun. But in a solar car, some of the light is converted to electricity by a device called a "solar cell." Each of the dark panels that you can see in the photograph contains many such solar cells. The electricity is used to drive the car's electric motor. Excess electricity is stored in a battery for cloudy periods.

This car was created large - 20 feet long and 6 feet wide - in order to catch a lot of sun. If we could make perfect solar cells that converted all the light falling on the car, its engine would have about 10 horsepower. But even the best of today's solar cells can convert only 20% to 24% of the sun's power into electricity. Therefore, under full sunlight, the motor puts out about 2 hp. With the help of the battery, output - for short times - can be increased to 8 hp. Most gasoline cars can put out up to 100 to 150 hp, and when cruising, use about 20 hp.

Because of the much lower power, this two-seater is very light (390 lbs) and highly streamlined. This permits it to reach a cruising speed of 56 and a maximum speed of over 87 miles per hour. In 1996, this car won the most famous of all races for solar cars. This race traverses the entire continent of Australia from tropical Darwin in the north to Adelaide on the southern coast. The race is run every day from 8 a.m. to 5 p.m.

The car covering the distance in the shortest total time wins. The Honda covered the 3010 km.- long race in 33 and a half hours at an average speed of 56 mph. Even though the car is Japanese, the car's most important components, the solar cells, were made in Australia. Professor Martin Green, a well-known researcher of solar cells, fabricated them at the University of New South Wales.

Many colleges and universities in the US have student teams building and racing solar cars. If you are old enough to go to college, you could select such a university and participate in building a solar car.

If you find solar-powered cars amazing, you will be even more amazed by solar-powered airplanes.

In 1980, DuPont offered a prize for the first plane powered by the sun to fly across the English Channel. On July 7, 1981, pilot Steve Ptacek flew a solar powered airplane, built in the US, from Corneille-en-Verin Airport north of Paris, France, to Manston Royal Air Force base in Kent, England.

Solar-powered airplanes gain power with altitude since the air gets thinner and hence there is more sunlight. This plane had more than 1 and a half times much power at 10, 000 feet than at the sea level at which it started

Solar-powered airplanes flying at above 80, 000 feet are being developed by NASA. The plan is to have these planes fly forever, like satellites, but at much lower costs.