By Justine Burt
At the Green Grid Forum in March 2012, several companies that host digital marketplaces and social networks highlighted their efforts to create greener data centers. Today data centers use more than 2% of all electricity. Approximately half of electricity in the U.S. is generated by burning coal. Rapidly rising data center energy use will contribute an ever increasing amount of greenhouse gas emissions unless we can decouple the growth of data storage and processing from fossil fuel pollution.
Data centers are the cell phone towers of this decade. Demand for their services is expanding quickly but their architects don’t want people to know they are there. So data centers are being disguised and hidden: in underground former NATO ammo depots, as large chicken coops in upstate New York, as mega-mansions with three underground stories in Minnetonka, Minnesota.
Data the world stores and processes will continue to expand quickly. Information infrastructure solutions company EMC estimates that in 2009 global data was 0.8 zettabytes (0.8 trillion gigabytes) and that number will grow to 35 zettabytes by 2020. Without an eye on data center efficiency and renewable power usage, the climate impact of data centers will grow exponentially as well.
A few years ago, data center managers on the bleeding edge were talking about using outside air to cool servers. Now the race to net zero (net zero energy, net zero electricity or net zero carbon) has become more complex.
Here are some of the ways data center managers are harnessing renewable energy and maximizing resource efficiency.
- Free cooling – Servers generate waste heat. Data center architects design air handling systems to move that heat out and away. Siting a data center underground where temperatures stay below 60 degrees F helps with cooling. So does co-locating data centers that use water for liquid cooling near a river, lake or sea. Green Mountain Data Center in Norway, which is carved into a mountain near a fjord, claims to have no carbon footprint.
- Building orientation – Facebook‘s Prineville, Oregon, data center buildings align with wind patterns to tap into free cooling. Building orientation ensures generator exhaust from one building will not blow into another building.
- Renewable energy – Data center managers seek low-cost renewable energy to power their data centers. Companies like AMD are studying whether it is better to site them near renewable energy and move the data over long distances or host the data near where it is needed and move energy over longer distances. An often cited example for abundant low-cost geothermal and hydroelectric resources is Iceland but the remote location makes data movement challenging.
- Server utilization – Average server utilization runs between 5 and 15%. One conference panelist explained that a client will request server space and then data center management will over-allocate server space to ensure they meet the client’s needs. The panelist told the audience that if a client says he needs hosting space for 500 transactions/second, they round up to 700 transactions/second and then double or triple that number. There are multiple ways to optimize space, though. One performance management company, Akamai, states that their server utilization is much higher than average, between 15 and 40%.
- Virtualization – Instead of dedicating separate servers for each program, virtualization software lets companies run multiple applications on the same server to save energy.
- Power distribution – Eliminating the number of times power changes voltage or runs through different pieces of equipment reduces power losses. Facebook’s Open Compute project states that the average total loss of power up to servers ranges between 21 and 27%. Prineville power loss averages 7.5%.
The definition of an ideal, sustainable data center continues to change over time as companies test innovations. Cutting edge ideas developed a few years ago are now considered best practices. As the world becomes more connected through mobile devices and the smart grid, it will be exciting to see what innovations data centers develop to balance their energy demand and supply and reduce their carbon footprint.
Justine Burt is a sustainability management system consultant in Silicon Valley specializing in sustainability project implementation. www.justineburt.com