Suddenly there is an explosion in solar research. It began three years ago and is accelerating fast. Huge mirrors are collecting the sun in Tokyo and Denver. Giant windmills are beginning to turn in Ohio. Engineers are already testing the tools astronauts will use in space when they build a 50-square-mile satellite that will radiate solar power down to Earth. Most surprisingly, huge machines designed to sit in the tropical seas and extract power from the hot water are about to be built. Much of the work is in America and Japan but Britain is closely involved - we have, it seems, already developed the necessary technology.

But can any of these techniques be ready for when oil becomes scarce in 15 or 20 years? Will any of them be cheap enough to displace nuclear power or coal from our energy future? Some of the answers are dazzling!