Businesses could save around £25 on each and every desktop PC they own, simply by ensuring they are powered down at the end of the day.

The simple job of powering down a PC can reduce a machine’s energy use by 80%, and is one step being recommended after a study reported that UK organisations waste as much as £300m a year powering idle computers.

According to the 2009 PC Energy Report released today by 1E and the Alliance to Save Energy, only 27% of UK workers power down their computers at the end of the workday – although that number compares favourably to the situation in the US, where only 10% do so.

“Despite spiralling energy costs and the environment playing an increased role in the corporate agenda, much further action is required by both individuals and employers” the bodies behind the study said.

The IT industry generates 2% of the world’s carbon emissions, and of this apparently up to 39% is created by PCs and monitors.

If a UK business with 10,000 computers leaves them on all night for one year, it will cost £168,000 and emit 828 tonnes of CO2, it has been estimated.

Products like 1E’s NightWatchman PC power management system or the Surveyor and Edison lines from Verdiem Corp allows the central administration of power management settings for networked PCs. Policies can be set up to power down machines or maximise energy savings by placing machines into lower power states without interfering with end-user productivity, desktop maintenance or upgrades.

The report is based on data resulting from two surveys conducted by market research firm Harris Interactive.