Half the electricity used by a PC is wasted, according to research by Google . The online search giant is teaming up with Intel and a number of PC and component makers to work towards improving computer efficiency.

Google's tests show that around 50 per cent of the electricity used by a PC is transformed into heat or otherwise dissipated in the conversion from AC to DC power. Computer servers waste around 30 per cent of the electricity they use.

"This is not a technology problem. We have power supplies with 90 per cent efficiency shipping today," Urs Hölzle, Google's fellow and senior vice president of operations, said in a statement .

The problem is cost, said Pat Gelsinger, senior vice president of the Digital Enterprise Group at Intel. Making a PC more power efficient in this manner adds about £10 to its retail cost, and it adds about £15 to the cost of a server. But at the same time, having an energy-optimised PC would reduce your electricity bill from around £15 to £10 per year and computer, Gelsinger added.

Reduce your bills

Announced yesterday, the Climate Savers Computing Initiative aims to develop more energy efficient components, power supplies and voltage regulators. This will enable PCs and servers to use 90 per cent or more of the electricity they get from the power socket by 2010. Microsoft , Hewlett-Packard , Dell and IBM are just some of the companies signed up to the Initiative

If this goal can be met, these power-efficient servers and PCs would save 71.6 billion kilowatts of electricity in that year, Gelsinger said. This would prevent some 54 million tons of carbon dioxide being released into the air that year. That's equivalent to the output from 11 million cars, or about 20 coal power stations.

Google said its own servers are between 90 and 93 per cent efficient.