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Why We Need a Speed Limit for the Internet

The energy use of the internet can only stop growing when energy sources run out, unless we impose self-chosen limits.

Always online. Image: MatthewG. CC.
Always online. Image: MatthewG. CC.
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In terms of energy conservation, the leaps made in energy efficiency by the infrastructure and devices we use to access the internet have allowed many online activities to be viewed as more sustainable than offline.

On the internet, however, advances in energy efficiency have a reverse effect: as the network becomes more energy efficient, its total energy use increases. This trend can only be stopped when we limit the demand for digital communication.

Although it’s a strategy that we apply elsewhere, for instance, by encouraging people to eat less meat, or to lower the thermostat of the heating system, limiting demand is controversial when applied to the internet, in part because few people make the connection between data and energy.

How much energy does the Internet consume?

How much energy does the internet consume? Due to the complexity of the network and its fast-changing nature, nobody really knows. Estimates for the internet’s total electricity use vary by an order of magnitude. One reason for the discrepancy between results is that many researchers only investigate a part of the infrastructure that we call the internet.

In recent years, the focus has been mostly on the energy use of data centers, which host the computers (the “servers”) that store all information online. However, in comparison, more electricity is used by the combination of end-use devices (the “clients”, such as desktops, laptops and smartphones), the network infrastructure (which transmits digital information between servers and clients), and the manufacturing process of servers, end-use devices, and networking devices. 1

A second factor that explains the large differences in results is timing. Because the internet infrastructure grows and evolves so fast, results concerning its energy use are only applicable to the year under study. Finally, as with all scientific studies, researcher’s models, methods and assumptions as a base for their calculations vary, and are sometimes biased due to beliefs or conflicts of interest. For example, it won’t suprise anyone that an investigation of the internet’s energy use by the American Coalition for Clean Coal Electricity sees much higher electricity consumption than a report written by the information and communication technology industry itself. 23

Eight Billion Pedallers to Power the Internet

Keeping all this in mind, we selected what seems to be the most recent, complete, honest and transparant report of the internet’s total footprint. It concludes that the global communications network consumed 1,815 TWh of electricity in 2012. 4 This corresponds to 8% of global electricity production in the same year (22,740 TWh). 56

If we were to try to power the (2012) internet with pedal-powered generators, each producing 70 watt of electric power, we would need 8.2 billion people pedalling in three shifts of eight hours for 365 days per year. (Electricity consumption of end-use devices is included in these numbers, so the pedallers can use their smartphones or laptops while on the job). Solar or wind power are not much of a solution, either: 1,815 TWh equals three times the electricity supplied by all wind and solar energy plants in 2012, worldwide. 7

Today’s internet can’t be powered by renewable energy. Image: Wikipedia Commons.
Today’s internet can’t be powered by renewable energy. Image: Wikipedia Commons.
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These researchers estimate that by 2017, the electricity use of the internet will rise to between 2,547 TWh (expected growth scenario) and 3,422 TWh (worst case scenario). If the worst-case scenario materializes, internet-related energy use will almost double in just 5 years time. Note that further improvements in energy efficiency are already included in these results. Without advances in efficiency, the internet’s energy use would double every two years, following the increase in data traffic. 8

Increasing Energy Consumption per User

Importantly, the increasing energy consumption of the internet is not so much due to a growing amount of people using the network, as one would assume. Rather, it’s caused by a growing energy consumption per internet user. The network’s data traffic rises much faster than the number of internet users (45% versus 6-7% annually). 9 There’s two main reasons for this. The first is the evolution towards portable computing devices and wireless internet access. The second is the increasing bit rate of the accessed content, mainly caused by the digitalization of TV and the popularity of video streaming.

The increasing energy consumption of the internet is not so much due to a growing amount of people using the network, as one would assume. Rather, it’s caused by a growing energy consumption per internet user.

In recent years we have seen a trend towards portable alternatives for the desktop computer: first with the laptop, then the tablet and the smartphone. The latter is on its way to 100% adoption: in rich countries, 84% of the population now uses a smartphone. 94 These devices consume significantly less electricity than desktop computers, both during operation and manufacture, which has given them an aura of sustainability. However, they have other effects that more than off-set this advantage.

First of all, smartphones move much of the computational effort (and thus the energy use) from the end-device to the data center: the rapid adoption of smartphones is coupled with the equally rapid growth in cloud-based computer services, which allow users to overcome the memory capacity and processing power limitations of mobile devices. 4 10 Because the data that is to be processed, and the resulting outcome must be transmitted from the end-use device to the data center and back again, the energy use of the network infrastructure also increases.

High-Speed Wireless Internet

Robbing Peter to pay Paul can improve the total efficiency of some computational tasks and thus reduce total energy use, because servers in datacenters are managed more energy efficiently than our end-use devices. However, this advantage surely doesn’t hold for smartphones that connect wirelessly to the internet using 3G or 4G broadband. Energy use in the network is highly dependent on the local access technology: the “last mile” that connects the user to the backbone of the internet.

A wired connection (DSL, cable, fibre) is the most energy efficient method to access the network. Wireless access through WiFi increases the energy use, but only slightly. 1112 However, if wireless acces is made through a cellular network tower, energy use soars. Wireless traffic through 3G uses 15 times more energy than WiFi, while 4G consumes 23 times more. 13414 Desktop computers were (and are) usually connected to the internet via a wired link, but laptops, tablets and smartphones are wirelessly connected, either through WiFi or via a cellular network.

Wireless traffic through 3G uses 15 times more energy than WiFi, while 4G consumes 23 times more. Image: jerry0984. CC.
Wireless traffic through 3G uses 15 times more energy than WiFi, while 4G consumes 23 times more. Image: jerry0984. CC.
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Growth in mobile data traffic has been somewhat restricted to WiFi “offloading”: users restrict data connectivity on the 3G interface due to significantly higher costs and lower network performance. 4 Instead, they connect to WiFi networks that have become increasingly available. With the advance of 4G networks, the speed advantage of WiFi disappears: 4G has comparable or improved network throughput compared to WiFi. 13 Most network operators are in the process of large-scale rollouts of 4G networks. The number of global 4G connections more than doubled from 200 million at the end of 2013 to 490 million at the end of 2014, and is forecast to reach 875 million by the end of 2015. 101516

More Time Online

The combination of portable computing devices and wireless internet access also increases the time we spend online. 10 This trend did not start with smartphones. Laptops were expected to lower the energy consumption of the internet, but they raised it because people took advantage of the laptop’s convenience and portability to be online far more often. “It was only with the laptop that the computer entered the living room”. 17

Smartphones are the next step in this evolution. They allow data to be consumed in many places in and outside the home, alongside more conventional computing. 18 For example, field research has revealed that smartphones are intensively used to fill ‘dead time’—small pockets of time not focused on one specific activity and often perceived as unproductive time: waiting, commuting, being bored, coffee breaks, or “social situations that are not stimulating enough”. Smartphones also have become to play an important bedtime role, being called upon last thing at night and first thing in the morning. 18

We are using our increasingly energy efficient devices for longer hours as we send more and more data over a worldwide infrastructure.

Noting these trends, it is clear that not every smartphone is a substitute for a laptop or desktop computer. Both are used alongside each other and even simultaneously. In conclusion, thanks to smartphones and wireless internet, we are now connected anywhere and anytime, using our increasingly energy efficient devices for longer hours as we send more and more data over a worldwide infrastructure. 1819

The result is more energy use, from the mobile devices themselves, and – much more important—in the datacenters and in the network infrastructure. Also, let’s not forget that calling someone using a smartphone costs more energy than callling someone using a dumbphone.

Increasing Bit Rates: Music & Video

A second key driver behind the growing energy consumption per internet user is the increasing bit rate of content. The internet started as a text-medium, but images, music and video have become just as important. Downloading a text page requires very little energy. To give an example, all the text on this blog, some 100 articles, can be packed into less than 9 megabytes (MB) of data. Compare this to a single high-resolution image, which easily gets to 3 MB, or a standard quality 8-minute YouTube video, which ticks off at 30 MB—three times the data required for all the words on this blog.

Because energy use rises with every bit of data, it matters a lot what we’re doing online. And as it turns out, we are increasingly using the network for content with high bit rates, especially video. In 2012, video traffic was 57% of all internet traffic (excluding video exchanged through P2P-networks). It’s expected to increase to 69% in 2017. 20

Trains are energy efficient. But mobile computing is not. Image: Nicolas Nova.
Trains are energy efficient. But mobile computing is not. Image: Nicolas Nova.
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If video and wireless internet access are the key drivers behind the increasing energy use of the internet, then of course wireless video is the worst offender. And it’s exactly that share of traffic that’s growing the fastest. According to the latest Cisco Visual Networking Index, mobile video traffic will grow to 72% of total mobile data traffic in 2019: 10

“When device capabilities are combined with faster, higher bandwith, it leads to wide adoption of video applications that contribute to increased data traffic over the network. As mobile network connection speeds increase, the average bit rate of content accessed through the mobile network will increase. High-definition video will be more prevalent, and the proportion of streamed content, as compared to side-loaded content, is also expected to increase. The shift towards on-demand video will affect mobile networks as much as it will affect fixed networks”.

Power consumption is not only influenced by data rates but also by the type of service provided. For applications such as email, web browsing, and video and audio downloads, short delays are acceptable. However, for real-time services—videoconferencing, and audio and video streaming – delay cannot be tolerated. This requires a more performant network, and thus more energy use.

Does the Internet Save Energy?

The growing energy use of the internet is often explained away with the argument that the network saves more energy than it consumes. This is attributed to substitution effects in which online services replace other more energy-intensive activities. 12 Examples are videoconferencing, which is supposed to be an alternative for the airplane or the car, or the downloading or streaming of digital media, which is supposed to be an alternative for manufacturing and shipping DVDs, CDs, books, magazines or newspapers.

Some examples. A 2011 study concluded that “by replacing one in four plane trips with videoconferencing, we save about as much power as the entire internet consumes”, while a 2014 study found that “videoconferencing takes at most 7% of the energy of an in-person meeting”. 2122 Concerning digital media, a 2014 study concludes that shifting all DVD viewing to video streaming in the US would respresent a savings equivalent to the primary energy used to meet the electricity demand of nearly 200,000 US household per year. 23 A 2010 study found that streaming a movie consumed 30 to 78% of the energy of traditional DVD rental networks (where a DVD is sent over the mail to the customer who has to send it back later). 24

Because the estimates for the energy intensity of the internet vary by four orders of magnitude, it’s easy to engineer the end result you want.

There are some fundamental problems with these claims. First of all, the results are heavily influenced by how you calculate the energy use of the internet. If we look at the energy use per bit of data transported (the “energy intensity” of the internet), results vary from 0,00064 to 136 kilowatt-hour per Gigabyte (kWh/GB), a difference of four orders of magnitude. 1218. The researchers who made this observation conclude that “whether and to what extent it is more energy efficient to download a movie rather than buying a DVD, or more sustainable to meet via videoconferencing instead of travelling to a face-to-face meeting are questions that cannot be satisfyingly answered with such diverging estimates of the substitute’s impact.” 12

To make matters worse, researchers have to make a variety of additional assumptions that can have a major impact on the end result. If videoconferencing is compared to a plane trip, what’s the distance travelled? Is the plane full or not? In what year was it built? On the other hand, how long does the videoconference take? Does it happen over a wired or a wireless access network? Do you use a laptop or a high-end telepresence system? When you’re streaming music, do you listen to a song once or twenty times? If you buy a DVD, do you go to the store by car or by bike? How long is the trip? Do you only buy the DVD or do you also shop for other stuff?

Time and Distance

All these questions can be answered in such a way that you can engineer the end result you want. That’s why it’s better to focus on the mechanisms that favour the energy efficiency of online and offline services, what scientists call a “sensitivity analysis”. To be fair, most researchers perform such an analysis, but its results usually don’t make it into the introduction of the paper, let alone into the accompanying press release.

One important difference between online and offline services is the role of time. Online, energy use increases with the time of the activity. If you read two articles instead of one article on a digital news site, you consume more energy. But if you buy a newspaper, the energy use is independent of the number of articles you read. A newspaper could even be read by two people so that energy use per person is halved.

High-end telepresence system. Image: Wikipedia Commons. Courtesy of Tandberg Cooperation.
High-end telepresence system. Image: Wikipedia Commons. Courtesy of Tandberg Cooperation.
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Next to time there is the factor of distance. Offline, the energy use increases with the distance, because transportation of a person or product makes up the largest part of total offline energy consumption. This is not the case with online activities, where distance has little or no effect on energy consumption.

A sensitivity analysis generates very different conclusions from the ones that are usually presented. For example: streaming a music album over the internet 27 times can use more energy than the manufacturing and transportation of its CD equivalent. 25 Or, reading a digital newspaper on a desktop PC uses more energy than reading a paper version from the moment the reading length exceeds one hour and a quarter, taking the view that the newspaper is read by one person. 26 Or, in the earlier mentioned study about the energy advantage of videoconferencing, reducing the international participant’s travel distance from 5,000 to 333 km makes travelling in person more energy efficient than videoconferencing when a high-end telepresence system is used. Similarly, if the online conference takes not 5 but 75 hours, it’s more energy efficient to fly 5,000 km. 22

Rebound Effects

The energy efficiency advantage of videoconferencing looks quite convincing, because 75-hour meetings are not very common. However, we still have to discuss what is the most important problem with studies that claim energy efficiency advantages for online services: they usually don’t take into account rebound effects. A rebound effect refers to the situation in which the positive effect of technologies with improved efficiency levels is offset by systematic factors or user behaviour. For example, new technologies rarely replace existing ones outright, but instead are used in conjunction with one another, thereby negating the proposed energy savings. 27

Not every videoconference call is a substitute for physical travel. It can also replace a phone call or an email, and in these cases energy use goes up, not down. 22 Likewise, not every streamed video or music album is a substitute for a physical DVD or CD. The convenience of streaming and the advance of portable end-use devices with wireless access leads to more video viewing and music listening hours 23, at the expense of other activities which could include reading, observing one’s environment, or engaging in a conversation.

A videoconference can also replace a phone call or an email, and in these cases energy use goes up, not down.

Because the network infrastructure of the internet is becoming more energy efficient every year—the energy use per bit of data transported continues to decrease—it’s often stated that online activities will become more energy efficient over time, compared to offline activities. 3 However, as we have seen, the bit rate of digital content online is also increasing.

This is not only due to the increasing popularity of video applications, but also because of the increasing bit rate of the videos themselves. Consequently, future efficiency improvements in the network infrastructure will bring higher quality movies and videoconferencing, not energy savings. According to several studies, bit rates increase faster than energy efficiency so that green gains of online alternatives are decreasing. 222324

Efficiency Drives Energy Use

The rebound effect is often presented as a controversial issue, something that may or may not exist. But at least when it comes to computing and the internet, it’s an ironclad law. The rebound effect manifests itself undoubtedly in the fact that the energy intensity of the internet (energy used per unit of information sent) is decreasing while total energy use of the internet is increasing.

It’s also obvious in the evolution of microprocessors. The electricity use in fabricating a microprocessor has fallen from 0.028 kWh per MHz in 1995 to 0.001 kWh per MHz in 2006 as a result of improvements in manufacturing processes. 28 However, this has not caused a corresponding reduction of energy use in microprocessors. Increased functionality—faster microprocessors—has cancelled out the efficiency gains per MHz. In fact, this rebound effect has become known as Moore’s Law, which drives progress in computing. 2728

While energy efficiency is almost universally presented as a solution for the growing energy use of the internet, it’s actually the cause of it. Image: miniyo73.
While energy efficiency is almost universally presented as a solution for the growing energy use of the internet, it’s actually the cause of it. Image: miniyo73.
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In other words, while energy efficiency is almost universally presented as a solution for the growing energy use of the internet, it’s actually the cause of it. When computers were still based on vacuum tubes instead of transistors on a chip, the power used by one machine could be as high as 140 kilowatt. Today’s computers are at least a thousand times more energy efficient, but it’s precisely because of this improved energy efficiency that they are now on everybody’s desk and in everybody’s pocket. Meanwhile, the combined energy use of all these more energy-efficient machines outperforms the combined energy use of all vacuum tube computers by several orders of magnitude.


In conclusion, we see that the internet affects energy use on three levels. The primary level is the direct impact through the manufacturing, operation and disposal of all devices that make up the internet infrastructure: end-use devices, data centers, network and manufacturing. On a second level, there are indirect effects on energy use due to the internet’s power to change things, such as media consumption or physical travel, resulting in a decrease or increase of the energy use. On a third level, the internet shifts consumption patterns, brings technological and societal change, and contributes to economic growth. 2728 The higher system levels are vastly more important than the direct impacts, despite receiving very little attention. 28

“The internet entails a progressive globalisation of the economy that has thus far caused increasing transportation of material products and people… The induction effect arising from the globalisation of markets and distributed forms of production due to telecommunication networks clearly leads away from the path of sustainability… Finally, the information society also means acceleration of innovation processes, and thus ever faster devaluation of the existing by the new, whether hardware or software, technical products or human skills and knowledge.” 27

Nobody can deny that the internet can save energy in particular cases, but in general the overwhelming trend is towards ever-higher energy use. This trend will continue unabated if we don’t act. There’s no constraint on the bit rate of digital data. Blu-ray provides superior viewing experience, with data sizes ranging between 25 and 50 GB—five to ten times the size of a HD video. With viewers watching 3D movies at home, we can imagine future movie sizes of 150 GB, while holographic movies go towards 1,000 GB. 24

Nor is there any constraint on the bit rate of wireless internet connections. Engineers are already preparing the future launch of 5G, which will be faster than 4G but also use more energy. There’s not even a constraint on the number of internet connections. The concept of the “internet of things” foresees that in the future all devices could be connected to the internet, a trend that’s already happening. 410 And let’s not forget that for the moment only 40% of the global population has access to the internet.

There are no limits to growth when it comes to the internet, except for the energy supply itself. Image: Gongashan.
There are no limits to growth when it comes to the internet, except for the energy supply itself. Image: Gongashan.
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In short, there are no limits to growth when it comes to the internet, except for the energy supply itself. This makes the internet rather unique. For example, while the rebound effect is also very obvious in cars, there are extra limits which impede their energy use from increasing unabated. Cars can’t get larger or heavier ad infinitum, as that would require a new road and parking infrastructure. And cars can’t increase their speed indefinitely, because we have imposed maximum speed limits for safety. The result is that the energy use of cars has more or less stabilized. You could argue that cars have achieved a status of “sufficiency”:

“A system consuming some inputs from its environment can either increase consumption whenever it has the opportunity to do so, or keep its consumption within certain limits. In the latter case, the system is said to be in a state of sufficiency… A sufficient system can improve its outputs only by improving the efficiency of its internal process.” 29

The performance of cars has only increased within the limits of the energy efficiency progress of combustion engines. A similar effect can be seen in mobile computing devices, which have reached a state of sufficiency with regard to electricity consumption—at least for the device itself. 29 In smartphones, energy use is limited by a combination of battery constraints: energy density of the battery, acceptable weight of the battery, and required battery life. The consequence is that the per-device energy use is more or less stable. The performance of smartphones has only increased within the limits of the energy efficiency progress of computing (and to some extent the energy density progress of batteries). 29

A Speed Limit for the Internet

In contrast, the internet has very low sufficiency. On the internet, size and speed are not impractical or dangerous. Batteries limit the energy use of mobile computing devices, but not the energy use of all the other components of the network. Consequently, the energy use of the internet can only stop growing when energy sources run out, unless we impose self-chosen limits, similar to those for cars or mobile computing devices. This may sound strange, but it’s a strategy we also apply quite easily to thermal comfort (lower the thermostat, dress better) or transportation (take the bike, not the car).

Limiting the demand for data could happen in many ways, some of which are more practical than others. We could outlaw the use of video and turn the internet back into a text and image medium. We could limit the speed of wireless internet connections. We could allocate a specific energy budget to the internet. Or, we could raise energy prices, which would simultaneously affect the offline alternatives and thus level the playing field. The latter strategy is preferable because it leaves it to the market to decide which applications and devices will survive.

Setting a limit would not stop technological progress. Advances in energy efficiency will continue to give room for new devices and applications to appear.

Although none of these options may sound attractive, it’s important to note that setting a limit would not stop technological progress. Advances in energy efficiency will continue to give room for new devices and applications to appear. However, innovation will need to happen within the limits of energy efficiency improvements, as is now the case with cars and mobile computing devices. In other words: energy efficiency can be an important part of the solution if it is combined with sufficiency.

Limiting demand would also imply that some online activities move back to the off-line world—streaming video is candidate number one. It’s quite easy to imagine offline alternatives that give similar advantages for much less energy use, such as public libraries with ample DVD collections. Combined with measures that reduce car traffic, so that people could go to the library using bikes or public transportation, such a service would be both convenient and efficient. Rather than replacing physical transportation by online services, we should fix the transport infrastructure.

In the next articles, we investigate the low-tech information networks that are being developed in poor countries. There, “sufficiency” is ingrained in society, most notably in the form of a non-existing or non-reliable energy infrastructure and limited purchasing power. We also discuss the community networks that have sprung up in remote regions of rich countries, and the designs for shared networks in cities. These alternative networks provide much more energy efficient alternatives for digital communication in exchange for a different use of the internet.



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Great piece, as always!

I’d add that another limitation to internet use is material resource use. The materials used to make electronic chips are not “conflict-free”.

A.B Prosper

I don’t know how I feel about your proposal but that was a smart and technologically proficient article. Well done.


Thinking of all the companies with animated intro videos, and the growing number of Retina/UHD/4K displays on the market, it made me think “Gosh, if only we had a format for vector video” only to swiftly realize we do.

It’s Adobe Flash, and it’s on its way out.

For content that is animated, not filmed, replacing Flash with grids of pixels, no matter how smartly they are encoded, isn’t going to compare to the bandwidth economy of a vector format.

I’d take it a step further and suggest creating a format for educational videos where you just stream text/markup and the client’s browser uses an appropriately ample library of vector 2D/3D “primitives” to render the content. One-time install of a large software package, then measly KB-sized streaming. Xtranormal/Plotagon/Nawmal boasted this, “Text-to-Movie”, but there are no energy efficiency gains in rendering them in datacenters then encoding them as raster videos to stream to users.

Thankfully Low Tech Magazine has drilled in the concept of Rebound Effect hard enough in me to have a healthy amount of doubt as to the efficiency of such a pipe-dream scheme.

Monica Hall

Jared, come read this, it’ll help pitch Pied Piper with hard data!


some modern thoughts to the rebound aka jevons effect of oil…video(ups) read here and here acn also arguent too much bandwidth brings us to much dopamine so we need ever more kicks same with oil energy etc…but i also explained in german how new inventions like the nylon nets and motorized fishery. replacing the inefficient hemp nets and rowing boats rebounds into exploited fisheries and more migration…positive feed back loop everywhere

Moshe Braner

In the USA at least, internet access (except via cellphone networks) is billed by the month, in effect making the light users subsidize the heavy users. Changing it to billing by the byte would be useful in encouraging low-bandwidth usage choices. But when they suggested than in Hungary some months ago riots broke out?! One can reduce ones usage of bandwidth by choosing to visit web sites that give more text and less imagery (and no video). Also, browser add-ons can be used to supress images and videos (most of which are superfluous advertising, although that’s the current funding source for much of “the internet” - another big topic).


The worst of all is that many ads are now videos. Almost nobody will watch it but they still run somewhere in the background and waste ressources. I try to block them but for instance at work i cannot and i see thos Videos running in many Tabs in the browser. Nobody really cares.

I guess all the text on this blog will fit on a old floppy disk if you omit the images.


Thanks, a great article once again, although I do not agree with the conclusion.

Actually the most efficient wired connection is also the fastest one - a 1 Gbps fiber-optical line consumes a little less energy, than a 30 mbps DSL, barely measurable in watts: win-win, just make sure the ISPs continue spreading their network (it’s a rather slow transition due to high installation costs). On the wireless-side I also believe people should return to the good old habit of sticking a cable in their devices - not just because of power usage, but also because those networks might have some other side-effects (maybe yet unknown, maybe known but not so much advertised).

…but as you correctly mentioned, if the technology keeps reaching higher average speeds, the content providers will roll out bigger and bigger amount of data. That’s the only part I can imagine being regulated by the law. Some 10-15 years ago in the IT education it was taught that a webpage shouldn’t exceed the size of 20 Kb, so everybody can access it easily. Nowadays? No limits, no recommendations, gigantopages. I would love a rule stating that every home/index page should be below 250 Kb. No place for embedded videos, HQ pictures, just the basics you want to see when visiting (yes, you can be proud, just like on this blog). People living in remote areas with slower connections would also welcome that. Though setting a speed limit for the whole acces is a no-no for me: some use the web as a read-only media, other listen to music on it, while others host servers. Completely different needs, whose broadband should be limited? Libraries and DVDs? Those are close to extinction for a reason (I have no personal problems with them, it’s just the truth).

Tilman Santarius

Hi Kris, a fantastic article. From first line to last, it speaks out of my heart. The suggestions on sufficiency limits are very very progressive (in the sense that public debate is not yet there at all, and will probably not be there for some time).

As of rebound effects, there is more that could be mentioned. For instance, motivational changes brought about through efficiency (i.e. “psychological rebounds”): the more efficient using the internet / mobile device will be, the more “ok” (desired, accepted) it is in terms of attitude, responsibility, behavior control.

Another aspect is what I call “strcutural rebound effects”: The efficiency improvements in IT have brought about social acceleration, have sped up our lives. It’s not only that we use mobil internet devices in spare times (e.g. in the train/car, in breaks), but using them also enables us to maximize our activities. For instance, modal split through smart mobility apps allows for more travel trips in one day etc. In effect, energy efficiency improvements speed up economic production, social interaction, and end-use consumption.

I have just finished a comprehensive book on rebound effects where I outline such and other effects - but it’s in German only. If you are interested (and able to read German), let me now!

Moreover, I am about to start a five year research group that will look at “rebound risks and sufficiency opportunities of digital consumption” from a sociological, economics, psychological , engineering and sustainable marketing angle. If that sounds interesting, let’s get in touch!


Insightful article as usual Kris, but I believe you have left unsaid ‘why’ increased energy usage is such a bad thing. In almost all of the comparisons where internet data usage is a substitute for an ‘offline’ process, stationary primary energy is replacing distributed fossil-fuel energy.

A kerosene powered data-centre displacing a kerosene-powered aeroplane flight is naturally worse when it comes to climate change and resource depletion, but where you have a data-centre powered by hydropower at a dam we might be willing to tolerate some inefficiency if it displaces the burning of petroleum. It is far easier for us to ensure cleaner sources of power for a North American data centre than for DVD factories in Vietnam or for fiercely air-conditioned cinemas in Singapore.

Anecdotally I feel that the true impact of distributed computing and communication has not been felt yet. Where I work we are shutting down regional offices and having people work from home with remote access to the HO server, we are also employing fewer people by having teleconferencing and video-conferencing interstate. Developing countries will not need any where near as much office space as was built in my developed city, and the existing office space may be retro-fitted into residential spaces as all of the files and desk-jobs move into the digital ether.


this is total nonsense.

the faster the internet, the less people will need to travel for work.

telepresence and other types of technologies, such as fast rendering of 3d printed prototypes, will also lower the need for transporting physical objects.

transport is , above all , one of the most wasteful of energy human endeavors. the less we need transport to achieve our ends, the more sustainable a system things become.

short of going back to the stoneage, the information society, replete with an ever accelerating internet bandwidth is one thing that will take us to a sustainable future.

worrying about speed limits is total utter nonsense, unless you are talking about the unsustainability of fast cars, fast trucks, the concord plane, space flight in general (let alone the joke idea of space tourism).

moving electrons is the path to a sustainable advanced civilization because electrons require ever lesser energy to travel fast.

Andrey L.

Video-streaming and music-streaming brought enormous changes to the cultural media market that the author totally ignores. Even the largest DVD rentals couldn’t possibly compete with the breath and deapth of what I can watch on streaming services. Same goes for music.

Going back to physical delivery of content would constrain choice, and restict availability based on minimum geographic demand - if you want to watch some indie Australian movie, but live in a city where not many people want to watch it, though luck, you can’t.

I know there are some activsits/thinker who lament this loss of “geographically-constrained cultural commonality” in that it forced, by limitation of past times, people to stick with a common much smaller sets of books, videos, music, food and even clothes styles, but I’m certainly not one that wants to revive these dreadful times.

Kris De Decker

@ Andrey

Seeing that you could store about 600 movies or 15,000 music albums on a 3 TB portable hard disk, I don’t think that physical distribution would lead to a less diverse culture. All the more because we could copy that content at home and distribute it further through the use of portable hard disks.

It’s a different approach, but it could have similar results. Digital storage media evolve at least as fast as internet connections and they both improve communication in an equal way.


A great and challenging article! I agree with most of it from the perspective of a datacenter/centralised model, but it shouldn’t be the only way to develop the Internet!

Enforcing energy prices that cover all its costs seems to be much more practical than setting speed limits, and it might also favour decentralised and less energy hungry technologies relying on P2P/mesh networks. Some research show that using the end point-devices capacities is significantly more efficient (for example ), and existing technology mixing bitorrent and the blockchain could be more efficient and diverse than both netflix-style services and physical distribution…

Did you come across more evidence about the P2P model during your research?

Sherwood Botsford

I question that 1.8 TWh figure.

Let’s do a ball park figure:

I’m a power user. I have both a laptop that I surf while sitting with my wife while she watches TV; I have a Mac Pro with 6 disks and 3 monitors. The laptop draw a few watts.

The mac pro, where I’m writing right now is drawing 200 w.

We have an internal network with a gigabit switch. It’s something like 8w, and the modem draws another 12 – wireless link to a tower 15 miles away.

So worst case I’m at 300 W. For everything, which is about 4 times what you are claiming per person for the world.

My computer is not the Internet.

Alas your link #4 where you claimed this figure is a turnip.

Now more realistically:

I have a remote webserver that I share a fractional virtual machine on. I think I have 1/20 of the virtual machine, and there are 16 VMs on the box. This is a non trivial server. Probably has a kW power supply. But 1/20 of 1/16 of 1000 is 3 w. My site ranks about 5 millionth.

For internet, I can’t count my internal network, but I should count my connection to the world. That’s about 12 W.

Yes I use other people’s sites. They use mine (now and then.) Overall, I can’t see this doubling my current useage. Call it 40 W. And, as I said, I’m a power user. I suspect that most people are 1/10 of this.

So 40 W * 8800 hours per year is about 360 kWh/year, or about $32 on my electric bill. That is the gas for ONE trip to the local library.

Don’t tell me we need to cut back on Internet.


You can switch YouTube to 144p resolution when watching videos. This greatly reduces the bitrate. It also makes your phone run cooler and last longer on one charge.


Some thoughts.

  1. As another comment mentioned, utility style per-byte billing would do wonders vs lump sum unlimited billing, as the latter does not create a useful incentive for either party. The supply company will be motivated to serve you faster internet as they will be paid for it. Users will be more likely to carefully consider the content they consume. It should be more like turning lights on and off.

  2. Energetics and efficiency are such hard things to measure, especially in a distributed entity with so much infrastructure changeover, ie. frequent updates of lines, towers, servers, and local machines. Lots of these are left out of calculations of efficiency. Certainly a home electric bill is no indication of the true cost of digital technology.

  3. When do limits really work? Be it drug prohibition or increased #’s of people in jail. Speed limit seems like a wrong way to go.

  4. A truly distributed internet, where something like local libraries stored local versions of common data, or neightborhood wireless servers acted as “lakes” of data. The cloud analogy of all transactions going to corporate servers is a way to extract a transactional tax.

Flynn Darby

I just discovered this site. Thank you for your well-written and well-researched analyses of problems like this one. Since this article was written, I’ve become troubled by the increasing bandwidth use of society as well, starting with my own real-world issue of hitting my 1 terabyte monthly bandwidth cap on my home internet connection in the USA. Could any of us imagine downloading 1 terabyte of data in a month 10 years ago?

I suspect that as time passes, high-definition video streaming will dwarf all other data consumed. When the first HD content surfaced in the late 90’s, it was a huge step forward, allowing consumers legitimate benefits to better see and understand what they were watching. Over the last 5 years though, this has now turned into a never-ending race to higher resolutions–4K and beyond–with little benefit to consumers. Even with a 65" TV, a person with normal eyes would need to sit no more than 8 feet away to even discern a difference between 4K and 1080p content. Now, TV manufacturers are increasingly pushing new 8K TVs, which have 16x as many pixels as a 1080p TV. Presumably, TV manufacturers and content producers alike will need to continuously increase resolutions to continue to sell new products and services. In 5 years, we may see 16K TVs, which would require 64x the bandwidth to stream content as 1080p.

My personal story on this resulted in my decision to revert to lower definition streaming, if only to stay under my bandwidth cap. I came to realize though that I couldn’t really tell much difference if I was streaming at 4K or 1080p, or in many cases, even lower resolutions. It seems like a ripe opportunity for regulation, a “speed limit” as you’ve proposed, or something. Because these gratuitous amounts of data are not benefiting anyone.

  1. Even the most complete studies about the internet’s energy use do not take into account all components of the infrastructure. For example, the embodied energy of the energy plants which are used to power the internet is completely ignored. However, if you run a data center or cellular tower on solar energy, it’s obvious that the energy it took to produce the solar panels should be included as well. The same goes for the batteries that store solar energy for use during the night or on cloudy days. ↩︎

  2. The cloud begins with coal: big data, big networks, big infrastructure, and big power” (PDF), Mark P. Mills, National Mining Association / American Coalition for Clean Coal Electricity, augustus 2013 ↩︎

  3. SMARTer2030—ICT Solutions for 21st Century Challenges” (PDF), Global e-Sustainability Initiative, 2015 ↩︎ ↩︎

  4. Emerging trends in electricity consumption for consumer ICT”, Peter Corcoran, 2013 ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎

  5. Key Electricity Trends” (PDF), IEA Statistics, 2015 ↩︎

  6. Of the total, 852 TWh was consumed by end-use devices, 352 TWh by networks, 281 TWh by data centers, and 330 TWh during the manufacturing stage. ↩︎

  7. Worldwide electricity production from renewable energy sources, edition 2013”, Observ’ER ↩︎

  8. The researchers also provide a “best case scenario” in which energy use increases only slightly. However, this scenario is already superseded by reality. It supposes slow growth of wireless data traffic and digital TVs, but the opposite has happened, as Cisco Visual Networking Index [11] shows. Furthermore, the best-case-scenario supposes a year-on-year improvement in energy efficiency of 5% for most device categories and an annual improvement in efficiency of the core network of 15%. These figures are well above those of past years and thus not very likely to materialize. The expected growth scenario supposes wireless traffic to grow to 9% of total network electricity consumption, and digital TV to stabilize at 2.1 billion units. In this scenario, energy efficiency improvements for devices are limited to 2% per year, while energy efficiency in the core network is limited to 10% per year. In the worst case scenario, wireless traffic grows to 15% of total network electricity consumption, digital TV will keep growing, and improvements in energy efficiency are limited to 1-5% annually for devices and to 5% in the core network. 4 ↩︎

  9. Measuring the Information Society Report 2014” (PDF), International Telecommunication Union (ITU), 2014 ↩︎ ↩︎

  10. Cisco Visual Networking Index: Global Mobile Data Traffic Forecast Update, 2014-2019”, CISCO, 2015. ↩︎ ↩︎ ↩︎ ↩︎ ↩︎ ↩︎

  11. Small network equipment key product criteria”, Energy Star, retrieved September 2015. ↩︎

  12. The energy intensity of the internet: home and access networks” (PDF), Vlad Coroama, 2014 ↩︎ ↩︎ ↩︎ ↩︎

  13. A close examination of performance and power characteristics of 4G LTE networks” (PDF), Junxian Huang, June 2012. ↩︎ ↩︎

  14. Energy consumption in mobile phones: a measurement study and implications for network applications” (PDF), Niranjan Balasubramanian, 2009 ↩︎

  15. 4G networks to cover more than a third of the global population this year, according to new GSMA intellligence data”, GSMA Intelligence, 2015 ↩︎

  16. Network equipment manufacturer Cisco notes in its 2015 report that “as mobile network capacity improves and the number of multiple device users grow, operators are more likely to offer mobile broadband packages comparable in price and speed to those of fixed broadband.” 10 If this becomes true, and a majority of internet users would routinely connect to the internet through 4G broadband, the energy use of the network infrastructure would more than double, assuming data traffic would remain the same. [4] That’s because from an energy perspective, the access network is the greedy part of any service provider’s network. The core network of optic cables is much more energy efficient. 4 ↩︎

  17. Are we sitting comfortably? Domestic imaginaries, laptop practices, and energy use”. Justin Spinney, 2012 ↩︎

  18. Demand in my pocket: mobile devices and the data connectivity marshalled in support of everyday practice” (PDF), Carolynne Lord et al., Lancaster University, april 2015 ↩︎ ↩︎ ↩︎ ↩︎

  19. Towards a holistic view of the energy and environmental impacts of domestic media and IT”, Oliver Bates et al., 2014 ↩︎

  20. “Cisco Visual Networking Index 2012-2017”, Cisco, 2013 ↩︎

  21. The energy and emergy of the internet” (PDF), Barath Raghavan and Justin Ma, 2011 ↩︎

  22. Comparison of the energy, carbon and time costs of videoconferencing and in-person meetings”, Dennis Ong, 2014 ↩︎ ↩︎ ↩︎ ↩︎

  23. The energy and greenhouse-gas implications of internet video streaming in the united states”, 2014 ↩︎ ↩︎ ↩︎

  24. Shipping to streaming: is this shift green?”, Anand Seetharam, 2010 ↩︎ ↩︎ ↩︎

  25. MusicTank report focuses on environmental impact of streaming platforms”, CMU, 2012 ↩︎

  26. Screening environmental life cycle assessment of printed, web based and tablet e-paper newspaper”, Second Edition, Asa Moberg et al, 2009 ↩︎

  27. Information Technology and Sustainability: essays on the relationship between ICT and sustainable development”, Lorenz M. Hilty, 2008 ↩︎ ↩︎ ↩︎ ↩︎

  28. Environmental effects of informantion and communications technologies”, Eric Williams, Nature, 2011 ↩︎ ↩︎ ↩︎ ↩︎

  29. Computing Efficiency, Sufficiency, and Self-Sufficiency: A Model for Sustainability?” (PDF), Lorenz M. Hilty, 2015 ↩︎ ↩︎ ↩︎