The big change next year will be a new USB PD (Power Delivery) standard, which brings much more flexibility and ten times as much oomph: up to 100 watts. In his London office Simon Daniel, founder of Moixa, a technology company, charges his laptop from a prototype souped-up USB socket. The office lighting, which uses low-voltage LED (light-emitting diode) lamps, runs from the same circuit. So do the monitors, printers and (with some fiddling) desktops. Mains power is only for power-thirsty microwaves, kettles and the like.