The energy impact of web searches is very low
Some myths are hard to kill. The Times Online “reports“:
Performing two Google searches from a desktop computer can generate about the same amount of carbon dioxide as boiling a kettle for a cup of tea, according to new research …
While millions of people tap into Google without considering the environment, a typical search generates about 7g of CO2 Boiling a kettle generates about 15g. “Google operates huge data centres around the world that consume a great deal of power,” said Alex Wissner-Gross, a Harvard University physicist whose research on the environmental impact of computing is due out soon.
The overhyping of the internet’s energy use goes back a decade, pushed by two right-wing deniers, Mark Mills and Peter Huber. They were actually using their easily-refuted analysis to argue against climate restrictions — I kid you not. In this 1999 press release [PDF] from the laughably-named denier group, the “Greening Earth Society,” Mills says:
While many environmentalists want to substantially reduce coal use in making electricity, there is no chance of meeting future economically-driven and Internet-accelerated electric demand without retaining and expanding the coal component.
I ended up writing a major report debunking this myth and then testifying in front of the Senate Commerce committee [PDF] (i.e. John McCain) and the House [PDF] on the subject. Jon Koomey and others at Lawrence Berkeley National Laboratory (LBNL) did even more work debunking this nonsense (click here for everything you could possibly want to know on the subject).
There are actually two mistakes in the Harvard calculation. The first, which was the focus of my research, is the big picture issue. What is the net energy consumed by the internet? I argue the internet is a net energy saver — and a big one — since it increases efficiency (especially in things like the supply chain) and dematerialization (it uses less energy to research online than in person). The fact that U.S. energy intensity (energy consumed per dollar of GDP) began dropping sharply in the mid-1990s is but one piece of evidence that internet- and IT-driven growth is less energy intensive.
I, for instance, am able to work at home and telecommute thanks to the Internet and a broadband connection. That saves the energy consumed in commuting and a considerable amount of net building energy: Most people’s homes are an underutilized asset, which consume a great deal of energy whether or not they are there.
The other mistake just involves the more narrow question of how much energy is consumed by Googling. Wissner-Gross says it is 7g of CO2 per search. My LBNL colleagues say that is way too high, and Google itself has rebutted that analysis with their own, which I reprint here:
Not long ago, answering a query meant traveling to the reference desk of your local library. Today, search engines enable us to access immense quantities of useful information in an instant, without leaving home. Tools like email, online books and photos, and video chat all increase productivity while decreasing our reliance on car trips, pulp and paper.
But 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. 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.
Recently, though, others have used much higher estimates, claiming that a typical search uses “half the energy as boiling a kettle of water” and produces 7 grams of CO2. We thought it would be helpful to explain why this number is *many* times too high. 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. Together with other work performed before your search even starts (such as building the search index) this amounts 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.
In terms of greenhouse gases, one Google search is equivalent to about 0.2 grams of CO2. The current EU standard for tailpipe emissions calls for 140 grams of CO2 per kilometer driven, but most cars don’t reach that level yet. Thus, the average car driven for one kilometer (0.6 miles for those in the U.S.) produces as many greenhouse gases as a thousand Google searches.
We’ve made great strides to reduce the energy used by our data centers, but we still want clean and affordable sources of electricity for the power that we do use. In 2008 our philanthropic arm, Google.org, invested $45 million in breakthrough clean energy technologies. And last summer, as part of our Renewable Energy Cheaper than Coal initiative (RE<C), we created an internal engineering group dedicated to exploring clean energy.
We’re also working with other members of the IT community to improve efficiency on a broader scale. In 2007 we co-founded the Climate Savers Computing Initiative, a group which champions more efficient computing. This non-profit consortium is committed to cutting the energy consumed by computers in half by 2010 — reducing global CO2 emissions by 54 million tons per year. That’s a lot of kettles of tea.
Bottom line: Google, YouTube, blog, and flickr as much as you want. If you are worried about your carbon footprint, buy 100 percent green power and do an efficient retrofit on your house to cover your emissions — and let the Internet keep saving people energy and resources.