Google serves up approximately 10 million search results every hour. How much does a web search cost? You don't pay up front, but there are non-monetary costs nevertheless. IT research firm Gartner estimates Google's data centres contain nearly a million servers, each drawing about 1 kilowatt of electricity. So every hour Google's engine burns through 1 million kilowatt-hours. Hence, it turns out that one search has the same energy cost as turning on a 100-watt light bulb for an hour.
