Google Power?

We put this to Eric Teetzel, Program Manager for RE(less than)C at Google:

RE(less than)C is an initiative that we started to advance technology and renewable energy, to make it cost competitive with fossil fuel power generation. We've done the calculations internally and I think anybody that's tried to do carbon accounting understands there's a lot of complications and nuance. The basic premise is that one Google search uses about 0.0003KWh worth of electricity. That's Ã?,± some and that then translates, based on emissions load, into somewhere around 0.2g of CO2 per search that we answer. To actually do the things that we do all of our online services require machines. Those machines are basically all housed in facilities we call data centres. Those machines are typically servers and networking equipment. The way in which we do the energy calculation per query - we look at not just the exact machines that touched the query as it comes in our data centre but we also look at allocating networking routing costs as well as what we would call just 'overhead.' It takes energy to build the index to be able to effectively answer the query as they come in. We also allocate those costs across all of our search presence. That's how we come up with the number of 0.2g per search or 0.0003kWh worth of electricity.