“Google’s big surprise: each server has its own 12-volt battery to supply power if there’s a problem with the main source of electricity. The company also revealed for the first time that since 2005, its data centers have been composed of standard shipping containers–each with 1,160 servers and a power consumption that can reach 250 kilowatts.” (from CNET)
There are lots of other choice tidbits about the design of the millions (?) of tiny servers that Google uses to run its data centers. Quite interesting.