Asked by: Gareth Lee, Bristol
Cloud computing is the idea that all our data and applications could be hosted by large companies like Google and Microsoft. The theory is that this will be greener, because a handful of massive server farms will use less power than a billion PCs. But, as you’ll know from the way your laptop warms up, data processing generates heat. In large data centres, cooling the racks of equipment will take as much electricity as powering the processors themselves.