I have read a news, which I want to share with all of you, that Finland's mobile network operators are testing alternative sources of energy -- such as wind and the sun -- as backup power for their phone towers. The search was prompted by last year's storms, which knocked out mobile networks across swathes of the country.

A mobile phone mast uses roughly as much power annually as a detached house that is heated solely by electricity.

Under normal conditions, the alternative sources can provide an average of 20 percent of the electricity needed to keep the tower humming. If there is a massive blackout and natural conditions are favourable, they can provide up to half the power it usually uses. That is enough to operate one of the two systems, 2G and 3G, that the tower usually carries -- at least until the grid is repaired.

The potential benefits of wind and solar power are twofold. Reduced electricity bills are a definite attraction for operators, but Elisa's Head of Mobile Access, Jouni Pekonen, claims another, more altruistic motive.

"There are a couple of reasons why we are investigating these new technologies," he says. "One of them is of course to try to lower our costs, and one important thing is to lower our carbon footprint."

Renewable energy has the potential to make mobile phone networks more reliable in poor weather conditions. The renewable sources would work as auxiliary supplies rather than replacements for electricity from the grid.

The technology has aroused international interest -- but so far remains unproven.