Summary James examines some ways to tap into alternative, hopefully inexhaustible energy. Solar power can work great based on solar cells, even for a sports car, but a more ambitious solar tower in Andalusia uses reflection from 'heliostats' (mirrors always pointed to the sun by computer-control). Captation in space, well a geostationary station at 32,000 km, is seriously planned, dependent on building a solar-powered space elevator to it. The deary Britis isles are unfit for solar energy, but rich in sea movement. It's used by tidal turbines, basically reversed windmills, and devices converting wave energy. Holland is ideal for windmills, but far more efficient is astronaut Wubbo Ockels' high tech kites project to use the Jet Stream at great height. In New Mexico's desert, petrol is produced synthetically from air using the sun-like heath from a solar oven. Oxford ha a research center for nuclear fusion.

• Documentary