Guardian: he smartphone has been called the fifth limb half of the UK's adult population has one, and 24% of us have tablets. Factor in the gadgets we house, such as electric toothbrushes and various entertainment devices, and it all adds up to a lot of juice. The 2007 report The Ampere Strikes Back suggested the energy burden of all our gadgets, especially huge plasma TVs, would undo the benefits of all other residential energy saving. Thanks to EU legislation and some manufacturers' work on energy efficiency,...