Microsoft has claimed that the software giant's new Internet Explorer 9 browser has the highest green credentials of current crop of web browsers.
"The more efficiently a browser uses power the longer the battery will last in a mobile device, the lower the electricity costs, and the smaller the environment impact," the firm said on the IE blog.
"While power might seem like a minor concern, with nearly two billion people now using the Internet the worldwide implications of browser power consumption are significant."
Microsoft posted graphs of a battery of their own tests of IE9, Firefox 4, Chrome 10 and Safari 5 with a "news site" test showing that IE9 drew 11.7W on average compared to 11.8W for Firefox and 13.5W for Chrome.
The figures meant IE9 was neck and neck with Firefox 4 but battery life would be nearly 40 minutes better using IE9 and Firefox 4 over Google's Chrome browser.
Microsoft said they worked with engineering teams at Intel in order to prioritise the reduction of power consumption. The tests haven't been verified with third parties.