Energy eternal

Nothing to it. Just squeeze the nuclei of two hydrogen atoms together and -- presto! -- out pops a helium nucleus, a neutron and a bloody great burst of energy. It's called nuclear fusion and the sun does it all the time. If it can power the stars, why not your SUV?

The fuel is cheap and plentiful: part heavy hydrogen (deuterium), which can be easily extracted from water, and part super-heavy hydrogen (tritium), which can be made from lithium, a reasonably abundant metal. The process is safe, no possibility of a runaway reaction, it requires relatively little fuel, and the very limited waste is much less radioactive than that of fission reactors. And it produces massive amounts of energy. The heavy hydrogen from a few gallons of water and the lithium in one laptop battery could fulfill the average person's energy needs for 30 years.

There is one small hitch, illustrated by the experimental reactor, Jet, in Oxfordshire, England. Jet requires more energy to start the reaction than it produces. Getting those nuclei close enough together is not easy.

But a big effort is being made to develop viable power. Building on the lessons learned from Jet, a $14-billion joint effort by the EU, Japan, China, South Korea, India and the U.S. will construct Iter, a prototype fusion reactor, in Cadarache, France. It is expected to produce ten times the energy required to initiate the reaction.

We must, however, be patient. Scientists predict that commercial viability is, most optimistically, at least 40 years away. But if it works, it will be energy heaven: cheap, reliable, safe, nearly waste-free and virtually limitless power. We will have captured the secret of the stars.