Bill Thompson has been doing some calculations…

According to research carried out by office equipment supplier Canon, based on figures from the National Energy Foundation and Infosource, more than six million PCs will be left on over Christmas, consuming nearly forty million kilowatt hours of electricity.

Together with the printers and other hardware they will waste enough electricity to microwave 268 million mince pies, pumping 19,000 unnecessary tonnes of carbon dioxide into the atmosphere, at a cost of around £8.6m…

He goes on to finger some unexpected power-wasting culprits:

As well as the computers in our homes and offices, it is also important to think about the energy we are using – and the carbon we are producing – by creating and maintaining a presence online.

The virtual server that hosts my weblog is on all the time, even when nobody is viewing my pages, and although its energy use is negligible, multiply that by 55 million or more blogs or 100 million MySpace profiles and you get some significant numbers.

It gets even worse with avatars. At the moment Linden Labs, who host the popular Second Life virtual world, has around 4,000 servers. Although they have two million signed up users, at any one time only around 15,000 people are logged on.

Blogger and technology writer Nicholas Carr did some rough calculations, based on the power consumption of each server being 200 watts and the power consumption of the logged-on user’s own PC being 120 watts, and reckons that each avatar uses 1,752 kilowatt hours of electricity – or about the same amount as an average person living in Brazil.

This works out at 1.17 tons of carbon dioxide per year, per avatar, or the same as driving a large car 2,300 miles.

Well, that’s decided it. No avatar for me, then!

And of course, all of this adds to the case for doing networking the Ndiyo way