Debunking the myth of the internet as energy hog, again: How information technology is good for climate

For some reason, the power used by computers is a source of endless fascination to the public. Most folks think that the power used by computers is a lot more than it actually is, and that it’s growing at incredible rates. Neither one of these beliefs is true, but they reflect a stubborn sense that the economic importance of IT somehow must translate into a large amount of electricity use. That incorrect belief masks an important truth: Information technology has beneficial environmental effects that vastly outweigh the direct environmental impact of the electricity that it consumes.

That’s the start of a guest post from Dr. Jonathan Koomey, a project scientist at Lawrence Berkeley National Laboratory. Koomey has been a friend and colleague for more than a decade and a half — and we’ve spent a lot of time debunking mis-analysis in this area (see “Ignore the media hype and keep Googling “” The energy impact of web searches is very LOW”).

The overhyping of the internet’s energy use goes back over a decade, pushed initially by two right-wing disinformers, Mark Mills and Peter Huber. I ended up writing a major report debunking this myth and then testifying in front of the Senate Commerce committee (i.e. John McCain) and the House on the subject. Koomey and others at LBNL did even more work debunking this nonsense (see links below).

Recently, someone sent me this UK Guardian story, “The dark side of cloud computing: soaring carbon emissions,” which asserted:

According to Joseph Romm’s 1999 seminal work, The Internet Economy and Global Warming, direct sales to consumers and decentralized digital inventories of goods could lead to dramatic reductions in energy consumption and greenhouse gas emissions by 2010.

However, things turned out differently. Each day we generate more and more data “” your digital footprint, so to speak, requires huge amounts of server space and energy. A part of that digital footprint may be described as digital waste “” just think about all the data that you have created online that you no longer use.

Well, it’s nice to have one’s work called “seminal” — and that paper might well be the single most cited study I ever wrote (with Art Rosenfeld and Susan Hermann). But like many seminal papers, people cite it without actually reading it!


The 1999 paper never said that the Internet would lead to “dramatic reductions in energy consumption and greenhouse gas emissions by 2010.” It said that the Internet would help significantly improve the efficiency of the overall economy, leading to a much faster rate of energy intensity decline than had been seen in the previous decade.

The Energy Information Administration initially scoffed at that prediction, but in fact, the EIA now reports that from 1986 to 1995, energy intensity (primary energy consumed per dollar of real GDP) dropped about 7.5%, whereas from 1996 to 2005 it dropped a whopping 20%! And it dropped another 8% from 2005 through 2009. Besides vindicating by prediction, it is one strongly suggestive piece of evidence that internet- and IT-driven growth is less energy intensive.

Focusing on the direct energy consumption of the digital economy simply makes little sense in trying to understand the overall impact of the Internet on the economy.

I asked Koomey if he wanted to respond to this piece. Besides his work at LBNL, he is a consulting professor at Stanford University and is one of the leading experts on the resource impacts of information technology and building efficiency technology. Here is what he wrote:

For some reason, the power used by computers is a source of endless fascination to the public. Most folks think that the power used by computers is a lot more than it actually is, and that it’s growing at incredible rates. Neither one of these beliefs is true, but they reflect a stubborn sense that the economic importance of IT somehow must translate into a large amount of electricity use. That incorrect belief masks an important truth: Information technology has beneficial environmental effects that vastly outweigh the direct environmental impact of the electricity that it consumes.

Back in 1999, a cleverly written article was published in Forbes magazine, claiming that the Internet used 8% of all US electricity, that all computers (including the Internet) used 13% of US electricity, and that this total would grow to half of all electricity use in ten to twenty years. Most major U.S. newspapers and business magazines, many respected institutions, and politicians of both political parties cited these assertions (the first one even came up in Doonesbury at about the same time). Alas, most people took leave of their critical faculties when evaluating them.

Joe Romm, Amory Lovins, and I spent a few person years of effort between us demonstrating in the scientific literature that these assertions were all false (for a compilation of that work, go here). The Internet, as defined by the Forbes authors, used less than 1% of US electricity in 2000, all computers used about 3%, and there is no way, short of repealing the laws of arithmetic, for the total to grow to half of all electricity use in one to two decades (see the Epilogue in Koomey 2008 for a summary). Joe also showed that the high-level statistics on growth in energy, electricity, and carbon emissions in the Internet era all showed exactly the opposite of what the above claims would imply: the growth rates were significantly lower in the Internet era (1996 to 2000) than in the preceding four year period, even though GDP growth was higher in the latter period.

Unfortunately, variations of these myths persist to this day. In early 2009, the normally reliable Sunday Times of London reported that generating the electricity needed for a Google search emitted half as much carbon as did boiling a cup of tea, but this claim proved to be spurious (see Mills and Koomey 2009). As recently as April 12, 2010, Energy Tribune published an op-ed by Robert Bryce repeating the falsehoods in the Forbes article and confusing several important issues on this topic. And the ongoing concern over total electricity used by data centers continues to generate news coverage (for example, see this article in the Guardian), even though these facilities use only about 1% of world electricity use and their efficiency is improving rapidly over time.

In my view, the really important story is that while computers use electricity, they are not a huge contributor to total electricity consumption, and while it’s a good idea to make computers energy efficient, it’s even more important to focus on the capabilities information technology (IT) enables for the broader society. Computers use a few percent of all electricity, but they can help us to use the other 95+% of electricity (not to mention natural gas and oil) a whole lot more efficiently.

As an example of this latter point, consider downloading music versus buying it on a CD. A study that is now “in press” at the peer-reviewed Journal of Industrial Ecology showed that the worst case for downloads and the best case for physical CDs resulted in 40% lower emissions of greenhouse gases for downloads when you factor in all parts of the product lifecycle (Weber et al. 2009). When comparing the best case for downloads to the best case for physical CDs, the emissions reductions are 80%. Other studies have found similar results (see Turk et al. 2003, Sivaraman et al. 2007, Gard and Keoleian 2002, and Zurkirch and Reichart 2000). In general, moving bits is environmentally preferable to moving atoms, and whether it’s dematerialization (replacing materials with information) or reduced transportation (from not having to move materials or people, because of electronic data transfers or telepresence) IT is a game changer.

Another area where IT can help us is in getting smarter and more capable, so we can use our resources more efficiently. This could take the form of better sensors and controls in buildings and industry, like the wireless sensor networks that can be quickly and cheaply distributed in existing structures without wiring. Or it could involve more widespread use of software to make better energy-related decisions, such as Lawrence Berkeley National Laboratory’s Home Energy Saver or the private sector tool called Wattbot, both of which I’ve worked on over the years. Or it could involve computer controls in automobile engines, which reduce criteria pollutant emissions and improve fuel economy at the same time. Or it might mean smart meters that track electricity use minute by minute. Or it might involve the various companies that scan utility bills for big corporations and “roll up” those bills into analysis software that gives companies visibility into their actual energy costs (see, for example, AdvantageIQ). All of these examples and more are enabled by cheap, abundant, and powerful information technology

And there is good reason to believe that trends in information technology are going to make these positive developments even more pervasive and important. We’re all familiar with Moore’s law, which describes the rate of change in transistors per chip over time (doubling every year from the mid-1960s to the mid-1970s, and doubling every two years since the mid-1970s), with correspondingly rapid reductions in costs per transistor. However, few people are aware that there’s a similarly regular trend on the electrical efficiency of computers that has persisted for two decades longer than Moore’s law, and applies to all electronic information technology, not just microprocessors. The electrical efficiency of computation, defined as the number of computations we can do per kilowatt-hour consumed, has doubled roughly every year and a half since the mid 1940s (see Koomey et al. 2009, below).

This trend has important implications for mobile computing technologies because these devices are constrained by battery storage. The power needed to perform a task requiring a fixed number of computations will fall by half every 1.5 years, enabling mobile devices performing such tasks to become smaller and less power consuming, and making many more mobile computing applications feasible. Alternatively, the performance of mobile devices could continue to double every 1.5 years while maintaining the same battery life (assuming battery capacity doesn’t improve). Some applications (like laptop computers) will likely tend towards the latter scenario, while others (like mobile sensors) will take advantage of increased efficiency to become less power hungry and more ubiquitous.

IT is one technology that should give us hope about meeting an aggressive warming limit of 2 degrees C (or less) from preindustrial times. Never before has society had to confront a challenge like this, but never before have we had such a powerful technology moving so rapidly in the right direction. And if we combine ubiquitous mobile computing with rapid advances in solar photovoltaic technologies (like in the Big Belly trash compactor, for example), the possibilities for truly game changing societal innovation are breathtaking

Of course, this story is as much about personal and institutional change as it is about technology, and without a focus on the human and organizational evolution (as well as a stiff price on carbon) we’ll continue on our currently unsustainable path. But one important piece of facing the climate challenge is falling rapidly into place: Information technology allows us to dematerialize, reduce transportation emissions, and get smarter faster. There’s no time to waste in putting it to work.

So Google, Youtube, blog, and flickr as much as you want. If you are worried about your carbon footprint, buy 100% green power and do an efficient retrofit on your house to cover your emissions “” and let the Internet keep saving people energy and resources.


Indeed, replacing material consumption and transportation with electricity is almost certainly a good thing from a climate perspective since it is considerably easier to generate carbon-free electricity than it is to have carbon free-transportation or carbon-free versions of books and newspapers and inventories and offices (see “An introduction to the core climate solutions”).

Related Posts:

Further reading

The best overall summary of the Forbes electricity use controversy can be found in the Epilogue to the second edition of my book Turning Numbers into Knowledge:

Koomey, Jonathan. 2008. Turning Numbers into Knowledge: Mastering the Art of Problem Solving. 2nd ed. Oakland, CA: Analytics Press. <> and <>

The key supporting work analyzing the Forbes claims is well documented in the following three articles (the first is a short summary in a technical magazine, and the second two are in peer reviewed journals):


Koomey, Jonathan. 2003. “Sorry, Wrong Number: Separating Fact from Fiction in the Information Age.” In IEEE Spectrum. June. pp. 11–12.

Koomey, Jonathan, Chris Calwell, Skip Laitner, Jane Thornton, Richard E. Brown, Joe Eto, Carrie Webber, and Cathy Cullicott. 2002. “Sorry, wrong number: The use and misuse of numerical facts in analysis and media reporting of energy issues.” In Annual Review of Energy and the Environment 2002. Edited by R. H. Socolow, D. Anderson and J. Harte. Palo Alto, CA: Annual Reviews, Inc. (also LBNL-50499). pp. 119–158.

Koomey, Jonathan, Huimin Chong, Woonsien Loh, Bruce Nordman, and Michele Blazek. 2004. “Network electricity use associated with wireless personal digital assistants.” The ASCE Journal of Infrastructure Systems (also LBNL-54105). vol. 10, no. 3. September. pp. 131–137.

If you have a genuine interest in this history, please email me and I’ll send you electronic copies.

The most recent summary of data center electricity use is the 2008 study I wrote for the peer reviewed journal Environmental research letters. I’m working on an update to this study now.

The 2008 study is this one:

Koomey, Jonathan. 2008. “Worldwide electricity used in data centers.” Environmental Research Letters. vol. 3, no. 034008. September 23. <>

The Google search = 50% x a cup of tea claim showed up in an article in the Guardian, and it was subsequently debunked in the following blog posting:

Mills, Evan, and Jonathan Koomey. 2009. Tempest in a tea-kettle. Berkeley, CA: Lawrence Berkeley National Laboratory. February 2. <>

The paper comparing CDs to downloads is this one:

Weber, Christopher, Jonathan G. Koomey, and Scott Matthews. 2009. The Energy and Climate Change Impacts of Different Music Delivery Methods. Analytics Press (also in press at the Journal of Industrial Ecology). August 17. <>

And here’s the paper on computing efficiency trends:

Koomey, Jonathan G., Stephen Berard, Marla Sanchez, and Henry Wong. 2009. Assessing trends in the electrical efficiency of computation over time. Oakland, CA: Analytics Press. (also in press at the IEEE Annals of the History of Computing). August 17. <>

Finally, here are those other references analyzing dematerialization of physical goods:

V. Turk, V. Alakeson, M. Kuhndt, and M. Ritthoff, The environmental and social impacts of digital music — A case study with EMI, 2003.

D. Sivaraman, S. Pacca, K. Mueller, and J. Lin, “Comparative Energy, Environmental, and Economic Analysis of Traditional and Ecommerce DVD Rental Networks,” Journal of Industrial Ecology, vol. 11, 2007, pp.77–91.

D.L. Gard and G.A. Keoleian, “Digital versus Print: Energy Performance in the Selection and Use of Scholarly Journals,” Journal of Industrial Ecology, vol. 6, 2002, pp. 115–132.

M. Zurkirch and I. Reichart, “Environmental Impacts of Telecommunication Services Two Life-Cycle Analysis Studies,” Greener Management International, vol. 32, 2000, pp. 70–88