Spending hours sat on your sofa playing console games isn't just bad for your health - it's bad for the environment and bad for your bank balance too. Update, 26/11/08: Greenpeace says the Nintendo Wii isn't very green.

The US Natural Resources Defense Council has undertaken some research into how much electricity is required to power each of the main games consoles.

It makes for scary reading, especially if you leave your console switched on when you're not playing it.

US games fans are likely to spend $160 per year on their Sony PlayStation 3 alone, just to keep the thing powered up, though the first version of the PS3 is not quite as bad, at $134. The consoles use just as much power when switched but not being played - something it seems many gamers are guilty of doing.

Microsoft Xbox 360 owners, meanwhile, are likely to fork out $143 if they bought the console when it first came out, while the updated version, launched in 2007, accounts for a slightly more modest $100 per year of the electricity bill.

"If you leave your Xbox 360 or Sony Play Station 3 on all the time, you can cut your electric bill by as much as $100 a year simply by turning it off when you are finished playing," said NRDC senior scientist Noah Horowitz.

Needless to say, British gamers are likely to have yet higher electricity bills by way of thanks for their devotion to the world of gaming. We don't have European energy consumption figures to hand to make a ready comparison, but utility bills in the US are markedly lower than those in Europe.

It's also fair to assume that the US Natural Resources Defense Council has a particular aim in mind in publicising these figures. Leaving your games console in standby makes a huge difference to the energy consumption figures: it costs only a tenth as much to run a PS3 if you remember to turn it off whenever you're not fulfilling your gangster dreams in Grand Theft Auto.

You don't necessarily have to get into the habit of switching off your gadgetry every time you've finished a gaming session either. Idle or standby modes are better than leaving the console switched on.

However, the US NRDC report points out that there are perfectly good power-savers built in to the consoles. "Automatic power-down features - which shut off devices if they are left idle for a certain amount of time - are big energy-savers. The feature exists in the Xbox 360 and was recently added to the Playstation 3, but it is rarely used and leaves room for improvement."

The Nintendo Wii console, however, emerges with a glowing report card. It costs just $15 a year to run in ruinous always-on mode, or $3 a year if its owner switches it off every time it's not being actively used. By comparison, the Sony PlayStation 3 uses five times as much electricity per year.

The good news, of course, is that by implementing the NRDC's suggestion of powering down your PS3 when you've finished annihilating baddies and saving the world, your leccy bill will drop by a factor of 10 too. Truly heroic.

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