Harnessing direct solar energy – a progress report
Box 2 | Driving on a sunbeam
Cars can run on sunlight – in fact, they can race on it. The World Solar Challenge car rally has now become a great Australian tradition, with teams from many countries keen to try their skill at building a solar-powered car and racing it the gruelling 3000 kilometres from Darwin to Adelaide.
The rules state that each car’s solar cells can only cover an area of 8 square metres, which is slightly less than the area of a small bathroom. And the cells can’t stretch out from the car like giant wings! But with a lightweight car and an efficient battery for storing extra power when the sun is bright, a solar car can manage a speed of 100 kilometres per hour and can continue – though usually much more slowly – on cloudy days or when the sun is low in the sky.
Of course, the cars in the solar challenge are expensive ‘one-offs’ and are not your average family sedan. Solar-powered motoring is still some way from being accessible to everyone. But it’s a start – in the same way that the great air races from Paris to London in the early part of this century honed the skills of aircraft designers, so that it eventually became possible to send jumbo jets around the world.
Probably the first widely used solar vehicles will be small cars with roof-mounted photovoltaic cells, batteries for electricity storage, and the ability to top up with mains electricity when left in the garage. Designed for commuting short distances in the suburbs, they will be built with the know-how accumulating from events like the World Solar Challenge. And when these vehicles do roll off the production line, we’ll all breathe more easily as a result!
Boxes
Box 1. Eliminating the zeroes
Box 3. Light to electricity
Box 4. The Big Dish
Box 5. Chemical fuels from the sun
Related sites
The University of New South Wales solar racing team (Australia)
Aurora Solar Car
World Solar Challenge
Solar car speed record smashed (by Sarah Kellet, Cosmos, 19 January 2011)
Solar power in a shipping container (by Tina Casey, Scientific American,
9 May, 2010)
Solar powered plane (by Zachary Shahan, Scientific American, 9 July, 2010)
Page updatedNovember 2011.