Iceland looks to serve the world

Not, you might think, the most obvious place to stick millions of the world's computer servers which are, for all their uses, rather less attractive.

The problem is that while these computers look innocuous, they use a lot of energy.

There is of course the power you need for the servers themselves, but almost as significant is the energy used to keep them cool.

"For every watt that is spent running servers," says Dr Brad Karp, of University College London, "the best enterprises most careful about minimising the energy of cooling and maximising efficiency typically find they are spending 40-60% extra energy on just cooling them."