The Carbon Footprint of a Web Search: Who's Green?

Takeaway: The energy used by a set of servers responding to a keyword search may be marginal, but they all add up to significant energy use.

The term "carbon footprint" is ubiquitous these days, and you're likely to see it mentioned in relation to everything from vehicles to the vegetables in your salad. But have you ever thought about the carbon footprint of a Web search? The energy used by the set of servers that responds to your keyword search is pretty marginal, but the total of all of these little interactions with technology can produce a big number in terms of energy use. But beyond trying to parse these tiny amounts of power into technical comparisons, is it possible to figure out who’s leading the pack in providing "green" Internet searches? Can we tell, for example, if Bing or Yahoo or any other contenders are making Google, the single-search colossus, look bad? Who’s really blazing the trail toward lower energy consumption while giving us all of those topical Web pages we look for every day? Here we take a look at some the data to try to figure this out.

The "Carbon Footprint" of a Single Google Search

Let’s start with the projected energy use of a single Google search. At the beginning of 2009, various media outlets were using estimates provided by a Harvard scientist, who estimated that a single Google search used about seven grams of carbon dioxide - about half the energy required to boil a kettle of water. Google countered the scientist's claim, stating that its search used about 1 kilojoule (kJ). A Google blog on the subject specified that the conversion to carbon emissions would result in a typical Google search generating just 0.2 grams of carbon dioxide; in other words, it would take quite a few Google searches just to get that kettle anywhere near lukewarm. Google repeated this figure in a report it released in 2011. (You can see a media report on this here.)

However, Google has also admitted that its CO2 estimate does not take energy the company is not responsible for - such as that consumed by users' computers - into account. Pinning down just how much energy a vast network of services such as those that Google provides can be a real challenge. But although trying to quantify Web searches in terms of kJ and CO2 grams may ultimately be futile, there are others ways to get a more concrete picture of the energy used by various big IT firms, including those that offer public search engines.

Google’s Green Tech Initiatives

Take Google as an example; this top player in search and other services has come up with some hard numbers, available directly from its website , that show how big the company’s carbon footprint is, and where that number can go based on changes to data centers and other operations. Google estimates that it generated 1.46 metric tons of CO2 in 2010, but offers a wealth of information on current efforts to lower that number, with strategies like best practices for data centers that include managing airflow, adjusting thermostats, and using "free cooling" as opposed to mechanical chilling equipment.

In addition, Google partnered with another big tech company, Intel, in 2007 to create the Climate Savers Computing Initiative (CSCI), a group that aims to drastically reduce carbon emissions in the IT industry.

According to the CSCI, the organization and its 700 members worldwide have been able to reduce CO2 emissions in their offices by 42-45 million metric tons per year. That's another really big number that illustrates a path toward greener tech company operations. The CSCI cites greater server efficiency, changes in desktop infrastructure, and "client power management deployment" as three top strategies for reducing IT's carbon footprint. As for quantifying the energy use of a search engine, Google claims that offering all of its services to a user for one month uses less energy than a few hours of lighting a home. That includes Gmail and other extras, as well as Google’s public search engine.

Additional Info on IT Energy Use

For more on the details about hardware-related energy use, green-tech obsessives can scour the Energy Star website, which provides details on how a business or home can cut carbon emissions with automatic shutoffs and many other kinds of common technology. Several tech consulting businesses also offer reporting on green tech benchmarks and current industry practices and trends.

Comparing Tech Companies: Who’s Green?

If all of this fails to provide a side-by-side comparison of the big tech companies, there’s another option: a website called RankaBrand attempts to compare the "green-ness" of tech companies according to some specific benchmarks, although none of these has to do with the kinds of very technical search engine energy estimates that caused such a stir in 2009. Instead, RankaBrand uses criteria such as:

• Does the company have a comprehensive plan for reducing power use?
• Has the company taken action to reduce or offset its carbon footprint?

Most of these assessment items have to do with policy, and the site uses different symbols for each one to show companies' relative progress. There’s even a section on labor conditions and fair trade that includes evaluation of third-party vendors.

The final outcome of this complex look into green IT policy puts Google at the head of the pack. Together with Gmail and YouTube, two Google holdings, the Google brand gets a top score of eight out of 10. MSN, Bing, and Hotmail, three Microsoft services, get a seven out of 10. Social media platform MySpace follows with five out of 10, and Yahoo and its Flickr photo site each get a four out of 10. Sites like eBay and Wikipedia score lower. Facebook, the colossal social media site, scores an abysmal one out of 10. (Editor's Note: These scores were accurate at time of writing but may change over time.)

Who's Leading the Charge?

In the end, this visual presentation of big IT brands is a rare assessment of how each of these companies is doing in an industry where carbon footprints are, in the end, extremely subjective. But comparisons like these, however rudimentary, do help individual info-seekers to develop their own ideas about who is leading the charge in smart, efficient computing for the future.