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One Per Cent: A New Scientist Blog

Internet responsible for 2 per cent of global energy usage

Jim Giles, consultant


(Image: Denis Doyle/Bloomberg via Getty Images)

How much energy does the internet use? It's hard to know where to start. There's the electricity consumed by the world's laptops, desktops and smart phones. Servers, routers and other networking equipment suck up more power. The energy required to manufacture these machines also needs to be included. Yet no one knows how many internet-enabled devices are out there, nor how long they are used before being replaced.

That hasn't stopped Justin Ma and Barath Raghavan from trying to answer the question. The pair, researchers at the University of California, Berkeley and the nearby International Computer Science Institute respectively, estimate that the internet consumes between 170 and 307 GW. Which, of course, raises another question: is that is a big number, or a small one?

Raghavan and Ma came up with their total by conducting a rough internet census. By drawing on previously published research, they estimate that our planet is home to 750 million laptops, a billion smart phones and 100 million servers.

They also put figures on the energy that it costs to produce each of these devices (4.5 GJ and 1 GJ for a laptop and smartphone respectively) and the period for which each is used before being replaced (three years for a laptop, two for a smart phone). Estimates for the energy that cell towers and optical switches use when transmitting internet traffic, plus similar calculations for wi-fi transmitters and cloud storage devices, helped complete the picture.

Their final answer sounds big. A gigawatt is a billion watts, so running and maintaining the internet is like illuminating several billion 100W bulbs simultaneously. But it's a small number compared with global energy use across all sectors. That figure is 16 terawatts, so the internet is responsible for less than 2 per cent of the energy used by humanity.

Raghavan and Ma suggest that attempts to create more energy-efficient internet devices, while worth pursuing, will not do much to lower global energy consumption. Instead, they propose that we should think about how the internet can replace more energy-intensive activities. Their calculations show that a meeting that takes place by video-conference uses an average of one hundredth as much energy as one in which participants took a flight so that they could sit down together. Replacing just one in four of those meetings by a video call, they add, would save as much power as the entire internet consumes.

The research will be presented next month at the Workshop on Hot Topics in Networks in Cambridge, Massachusetts.

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I think you also have to take into account how much energy you already saved by using the internet. That is of course very difficult to measure, but still, the use of internet must already save a lot of energy.


Nice piece of research.

Which, of course, raises another question: is that is a big number, or a small one?

And one that is too rarely asked. People frequently assume that a large number must be a "big number" (e.g. the often repeated myth that leaving appliances on standby is a problem).


Fred has a good point - I have downloaded hundreds of papers for research but if I had travelled to find a hard copy and then photocopied them I would have used way more power. That said, 2% is a pretty staggering amount of power!


Energy consumed by all the PCs in the world (when they are on!), as well as all the local hubs, regional data centers, company servers, the transmission lines run by telecoms and intermediate
routers, etc.

But Internet saves enormous energy as the paper usage otherwise is saved. Paper means cutting trees. Also Paper is also energy intensive industry.

Infact Internet has made the world shrinking. Press of a botton, the information is before your eyes.

Here are measures to save Energy on the Internet:

Measure you can take right now to save energy is to start entering Google searches at a clone site that uses a black background called Blackle. According to an estimate, if Google turned from white to black, that would save 750 Megawatt-hours a year.

Networking power management allow the computers in your network to save energy. For example, the most common networking power management feature is Wake on LAN (sometimes referred to as WoL). Wake on LAN allows the computer to be woken up from sleep by desired network traffic.

Dr.A.Jagadeesh Nellore (AP),India
E-mail: anumakonda.jagadeeshgmail


Your math on the light bulbs is a little off. A gigawatt (1 billion watts) is not several billion 100W bulbs lit simultaneously. Even 1 billion 100W bulbs would use 100 gigawatts. The actul answer is 10 million 100W bulbs.


I like this kind of rough, global calculation. It gives us a sense of where we are. But I think it's misleading to label the energy required to manufacture and run every computer or phone as "energy consumed by the Internet". Computers are also used for word processing, playing games, etc. And I know some people who occasionally use their phones for other things than browsing the web, like making calls (crazy, I know).


Thanks for the article, Jim. To answer Martin Omander's question, we actually weight devices differently according to how much of the device is used for Internet purposes. This sort of weighting is standard methodology for studies involving embodied energy. I highly encourage everyone to read the paper itself, titled "The Energy and Emergy of the Internet". The paper is not too long.


Re Dr. A Jagadeesh's comment on using Blackle to save energy. First, are you aware that the colors displayed on your screen by Google, or any web site, are entirely within your control? I prefer white text on a black background myself, and it is what I'm seeing as I type this.

Second, it probably isn't going to save energy. If you have an LCD display, it's backlit by a fluorescent tube or LEDs, which are always on (unless the display is blanked). A black pixel is created by the liquid crystal blocking the light at that point.


As Martin said - it's pretty misleading to say this is due to "The Internet" - actually it's very very misleading.

A little more precision would be cool, please?


Some historical perspective would be nice. What % of electricity did Telegraphs use in their heyday ? I have in my mind's eye a nice timeline including radio , TV , newspapers , maybe even Egyptian obelisks.


A question to Raghavan and Ma:

In what period of time did you consider the internet usage? Looking superficially at the sources, I presume you studied the internet in a time span roughly between 2005 and 2010 (a kind of average internet). Am I right?

This information would be important for future diachronic studies: is the global energy usage for internet growing or not?


This analysis is good, since there have been lots of calculations of this number with dubious sources. But the 2% measure is biased - it doesn't break down by region. Countries like the US and those in Europe use a disproportionate share of Internet traffic. Many countries have little to no Internet access (e.g. African and parts of Asia), yet consume significant amounts of power.

So, while the worldwide consumption my be 2%, it ignores that fact that Internet access is not equal. The figure for the US should probably be doubled by its percent of Internet users, bringing the US total to at least 5%.

The other problem is that, according to a study by Cisco, Internet access is expected to go up 4 times by 2016, with power use in advanced countries rising at only about 1% per year. So, the Internet, as virtualization expands, will take an ever-larger share of the energy budget.

In countries just getting Internet access, virtualization is a worthwhile goal. But when the whole world is virtualized, the Internet will become the Number One target for sustainability efforts.

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