by Tony Sirna

This post is part of sustainablog‘s fundraising blogathon for Dancing Rabbit Ecovillage – please consider making a donation.

Never underestimate the ability of completely erroneous information to propagate itself on the internet, especially if it makes for good headline material.

As I was doing some research on the ecological impact of the internet I kept coming across references to how two Google searches creates more carbon than making a pot of tea and how the internet uses almost 10% of the electricity in the US and may some day account for 50%. From what I can tell all of these are gross exaggerations and I won’t even bother linking to them.

The first issue is that some reports attribute all the energy used by home computers to the impact of the internet. While its true that the internet has probably increased the number of home computers and the amount of time spent on them, its hard to tell how much to attribute to the internet. Plus, more computer use has often meant less time in front of a TV, which maybe balances things out. I personally think its best to separate home computer impact and the impact of servers and internet infrastructure. See my post on reducing your computer’s eco impact for more on the former.

How Much Electricity Does the Internet Use

The internet is very electricity intensive. There are millions of servers that run 24/7 to provide us with all those billions of web pages and emails. These servers are generally collected together in ‘server farms’ which then require air conditioning to keep them from overheating.

Its a little out of date, but this study from Jonathan Koomey in 2007 says that worldwide, internet servers used about 120 billion kWh in 2005 which was double the amount used in 2000 (For the US the figure is about 45 billion kWh for 2005 or 1.2% of our electric use). About half that energy can be attributed to the cooling equipment, and not to the servers themselves. That same study says, given various assumptions, “total electricity used by servers by 2010 would be 76% higher than it was in 2005.” That gives us about 80 billion kWh per year for the US alone.

(Note: More electricity is used by the networks that transmit the internet, phone and other data. I couldn’t get clear data on that right now so I’ll have to leave that to another post)

Whats Your Share of Internet Impact

In the US there are 228 million internet users (about 75% of the population). Dividing 80 billion by 228 million gives us about 350 kWh per US internet user per year. Worldwide there are around 1.7 billion internet users and 210 billion kWh used, or about 120 kWh per internet user per year.

How does that compare to the energy used by your home computer?

If you are running a desktop, you might be using more energy at home than your share of the internet’s electricity use (approx. 460 kWh/year for a desktop running 8 hours a day). But if you are using an energy efficient laptop for 8 hours a day you might be using under 50 kWh/year, which makes your share of the internet look huge – 7 times as much as your home computer. Thats a big deal if you are living on an Ecovillage and trying to reduce your footprint to something sustainable.

Embodied Energy of Computers

What about the embodied energy of servers? For home computers, about 50% of their carbon impact is in their production, whereas for servers, the figure is more like 10% because servers run all day long so take more energy during their use. That said, there is also the embodied energy of all of equipment at the server farm that keeps things running: computer racks, routers, switches, air conditioning units, the building itself, etc.

Reducing the Impact of the Internet

Since power consumption for servers is so high, a lot of thought is going into how to reduce the energy needed. Some things on the table include:

  • More efficient servers in general
  • Servers that can run at higher temperatures so they don’t need cooling – this could cut energy use by up to half.
  • Using onsite electricity generation that uses the waste heat to run the cooling system. This is similar to whats called Combind Heat and Power where heat from generating electricity is used to heat a building
  • Distributed generation of power can help reduce transmission losses (see Bloom Energy)
  • Putting Server Farms in Cold Places (OK I just made that up – but maybe its a good idea)

Eco Benefits of the Internet

A study from 2008 by the American Council for an Energy Efficient Economy claims that for every unit of energy the internet takes, there are 10 units in energy savings. They base their findings on the increasing efficiency of our economy, since 1996 when the internet took off. I’m not sure how accurate their figures are but thats at least some good news.

This post is part of sustainablog‘s fundraising blogathon for Dancing Rabbit Ecovillage – please consider making a donation.

One Response to “What is the Carbon Footprint of the Internet”

  1. [...] been blogging away during the event, and has one more up on the carbon footprint of the internet (including a sweeping dismissal about “exaggerated claims” of the carbon footprints of [...]

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