Google defends its carbon footprint

13 January 2009

Google has responded to recent allegations that using its service contributes to global warming, saying that the estimates of energy use for searches far exceeded reality.

A study by Harvard physicist Alex Wissner-Gross, claiming that two Google searches results in the same amount of carbon dioxide as boiling water for a cup of tea, appeared in the Sunday Times of London. The report was widely picked up by the world media, hitting local TV news in the US. (See: Google searches generate 1,400 tonnes of CO2 daily: report

Responding to the report, Google said in its official blogspot  ''…as computers become a bigger part of more people's lives, information technology consumes an increasing amount of energy, and Google takes this impact seriously. That's why we have designed and built the most energy efficient data centers in the world, which means the energy used per Google search is minimal.''

Urs Hölzle, senior vice president of operations, referring to the earlier study, wrote, ''We thought it would be helpful to explain why this number is *many* times too high.'' ''In fact, in the time it takes to do a Google search, your own personal computer will use more energy than Google uses to answer your query,'' he said.

Google is fast - a typical search returns results in less than 0.2 seconds. Queries vary in degree of difficulty, but for the average query, the servers it touches each work on it for just a few thousandths of a second, it said.

Together with other work performed before your search even starts (such as building the search index) this amount to 0.0003 kWh of energy per search, or 1 kJ. For comparison, the average adult needs about 8000 kJ a day of energy from food, so a Google search uses just about the same amount of energy that your body burns in ten seconds, it added.