Google says a tool it designed for householders to measure their electricity use is so successful that utility companies around the world have signed up to extend it across their customer base.

The technology, Google Power Meter, only works in homes with a ‘smart’ meter, an electronic device which measures power consumption in more detail than a standard dial meter. The Google software allows users to hook their computers up to the meter and analyze their usage, giving them a better idea of when and how they might be able to cut their power costs. The system appears to let users make a note of when particular devices are switched on and measure their direct effect on power consumption – and the associated costs.

The firm has now signed deals with six US power companies, plus firms in Canada and India, which already have smart meters in many or all of their customers’ homes. Google says the scheme is currently only available to some customers, but will be rolled out later this year.

Google is also working with Itron, a firm which helps 8,000 utility firms run smart meter schemes, to integrate Google Power Meter with its technology. Meanwhile General Electric says it is working on a project to produce smart meters which have the Google tool built-in directly.

The big change with Google’s system is that it harnesses the information from smart meters for the consumer’s use. Generally, smart meters are designed mainly to provide utility firms with more detail on patterns of use so that they can anticipate spikes in demand. There have been fears that ‘smart grids’ which connect such meters wirelessly could be vulnerable to hackers.