Why are there no solar cars on our roads?

 Even in tropical countries? Even on sunny days? . That amazing solar car uses just 1.2 kW of power - about as much as a small toaster or 20 old electric lamps. A real electric car needs more like 10-15 kW - so over 10 times more. The other day I took a photo of a large house with a totally solar roof, and that produces about 4kW at best. So to power a real electric car, you would need an area of solar cells big enough to cover about 3-4 house roofs... and you simply can't fit that many solar panels on a car. But wait! Solar panels could still be used to top up the batteries in an electric car... or to produce hydrogen for a fuel-cell car, which we'll explore next...