I just saw a reference to a New Scientist article, Search engines’ dirty secret – 31 March 2010 about the energy use of search engines, such as Google. The author, James Clarage, who is a physicist at the University of St Thomas in Houston, does some rough calculations to show alarmingly high energy costs:

Google serves up approximately 10 million search results per hour, so one search has the same energy cost as turning on a 100-watt light bulb for an hour…We’ve all heard the future of information architecture is cloud computing. It just might be a cloud of carbon dioxide.

Tim Rustige had the same reaction I did: Yes, web searches use energy, but it can’t be that much. In New Scientist 3rd April 2010 ‘Search’s dirty secret’ he runs through some more detailed calculations to show that the energy use by Google is much less, perhaps 1% of what Clarage estimates.

Neither author takes into account the energy us of the home computer or smart phone that access Google. That’s likely to be many times the cost of what Google does. When that’s factored in, along with the costs of manufacturing, servicing, shipping, and disposing computers, it’s clear that Clarage’s basic point is still valid. There is a serious environmental impact of search engines and computers, and much needs to be done to improve their efficiency.