A single Google query consumes as much energy as an 11-watt light bulb does in one hour

Photo by Knut

This article from tagesschau.de (German) claims that a single Google search query (taking less than a second) consumes as much energy as an 11-watt light bulb does in one hour. This number is based on the total number of servers Google is running, the total energy consumption of those servers, and the total number of search queries processed.
Rolf Kersten estimates that running a single Google query releases 6.8 grams of CO2 and consumes a bit less—2 to 8 watt-hours of energy.
(Thanks to Mareen for combing the German language publications.)