Direct electricity use of the Internet is probably around 10% of total electricity consumption, said Jon Koomey Research Fellow at Stanford University but he immediately added that the number does not tell us very much.

Koomey, who has been studying Internet energy effects since 2000, was a keynote speaker at Google’s ‘How green is the Internet?’ summit, held June 6 at the Googleplex. There experts discussed the system-wide energy implications of information technology.

First of all there is the data gap. Ironically, IT -master of data collection- falls short when it comes to gathering extensive and well-defined data about its own energy consumption. Secondly, electricity is only a part of the Internet’s total energy cost, fabrication of equipment should also be taken into account. Last and perhaps most important when it comes to getting a good measure of the Internet’s overall environmental impact are system effects. These are IT-enabled energy savings in larger scale systems like transportation or manufacturing.

physical internet
Of all the different network components the ones that consume the most electricity are end user devices. Per unit they don’t use much, desktops and notebooks run on 200 and 70 kWh/year respectively. But the numbers add up: 1.6 billion connected PCs and notebooks and 6 billion mobile devices.

Koomey notes that energy efficiency of computing has doubled every 1.5 years for more than six decades bringing us low-power devices like phones (2 kWh/year) and tablets (12 kWh/year). Reduced power requirements foster a shift in the product’s life cycle energy costs. Electricity intensive devices gobble up 80% of their total energy in the use stage against 20% in the manufacturing stage. For low-power devices it’s the other way around, 80% is embodied energy. So in terms of energy savings the highest gains can be obtained in the production process.

Data centers
The second largest power users are the data centers. Together they consume 1 to 2% of the world’s electricity, according to Eric Masanet Associate Professor at Northwestern University. Masanet told the audience that massive energy saving can be made by moving business applications like e-mail and productivity software to the cloud. Many companies host their own small inefficient server rooms. Migrating locally hosted services to large datacenters could reduce energy cost by 87%. The benefits are the result of replacing millions of inefficient servers for a significant smaller number of efficient ones.

Data gap
Masanet agrees with Koomey that there is not enough data to get a good grip on the environmental impact of the Internet. Another difficulty is the lack of standardized research methods. Disparate system boundaries and nontransparent use of data makes it difficult to compare and integrate different studies. To address the problem Masanet and his fellows created CLEER, a publically available model for assessing energy effects of cloud computing.

System effects
Even though the Internet consumes a lot of electricity its net environmental impact can be a positive one, Koomey pointed out. Information technology can realize energy savings in larger systems. One consequence of IT is dematerialization, moving bits instead of atoms. To illustrate Koomey referred to a study by him and two colleagues in which they compared the environmental effect of buying a CD versus downloading music. Depending on the scenario downloading was 40% to 80% less harmful in terms of CO2 emissions.
Another example is smart parking. A sensor network covering parking spaces can alert drivers of an empty parking spot. That information will reduce the amount of time drivers are circling around looking for a place to park. A network covering 40.000 spots consumes only 15W annually while contributing to reducing CO2 emissions of cars.