Is the Cloud a Green Choice? And Why Should We Care?

Purposeful View: Environmental Impacts of Cloud Computing (by Barbara Eckman, Ph.D., 27 July 2011)


The popular wisdom is that cloud computing is “greener” because it results in fewer emissions of greenhouse gases (GHGs) like carbon dioxide, methane, nitrous oxide, and certain fluorinated gases, than traditional data centers. Moving to cloud computing saves resources and energy, because of higher resource utilization and greater power efficiency. That’s greener, right?

Not necessarily. While moving to the cloud will likely lessen your own enterprise’s carbon footprint, it may result in a net increase in GHG production, if your enterprise is located in an area rich in sustainable energy sources, but the cloud data center is not. Cloud data centers, typically located where energy is cheap, often get a higher percentage of their electricity from coal-powered plants, which are known to produce much higher levels of GHGs than those using energy sources such as hydropower, solar and wind. On the other hand, some cloud providers are intentionally locating their data centers in areas where sustainable energy is abundant. For example, Yahoo! recently opened a large data center in Buffalo, NY, using a large percentage of energy from hydropower, and cooling the center using prevailing winds coming off Lake Erie. This type of cloud computing can yield both greater power efficiency and fewer GHG emissions.

Determining the greenness of the cloud can be more complicated than it looks. The entire supply chain must be considered. For example, David Talbot in the MIT Technology Review (“Greener Computing in the Cloud”, 2009) quotes Yale’s Jonathan Koomey:

When people surf the Web – downloading pictures from sites like Facebook and videos from YouTube – they guzzle energy as data centers serve that content. But if you isolate the act of downloading a CD's worth of music, it turns out to be between 40 percent and 80 percent more efficient than acquiring a physical CD, if you take into account the energy inputs involved in manufacturing and transporting the CD.

GHGs are not the only measure of environmental impact. The sustainable use of the world’s freshwater resources is recognized as one of the most urgent challenges facing society today. The World Health Organization recently estimated that 1.1 billion people lack access to safe drinking water. Limiting the use of fresh water in cooling data centers is thus another important measure of greenness, one which Yahoo! ingeniously addresses by locating its Buffalo data center where it can be cooled by evaporation on all but a very few days of the year.

Why should we care if the cloud is green? A 2008 Forrester report (“A slowing economy won't slow down corporate green IT initiatives”) outlines corporations’ motivations for pursuing a green IT agenda. While reducing energy bills led the list, other motivations were also significant: regulatory compliance and aligning with business-wide green plans. Current and future government regulations and tax incentives for green enterprises can form a strong motivation. Until recently, this has been perhaps a stronger factor in Europe and Australia than in the US. But the US EPA recently has begun initiating programs like “40 CFR Part 98,” the Greenhouse Gas Reporting Program. Corporations’ interest in green IT is also motivated by seeking greater cultural legitimacy or a better corporate image. Consumers and potential employees, particularly those in younger age groups, are increasingly active in seeking information regarding the sustainability policies of businesses. Many corporations actively seek to be good neighbors to the communities in which they’re located, and green practices are often seen as an important component of these activities. If cloud computing is indeed a greener option, companies who embrace it can legitimately claim to be responsible for lessening the destruction of human life and property that global climate change might otherwise have caused.

In our view, cheap, renewable power sources are important but not sufficient in siting a cloud data center. Also required are: a stable government, a good supply of technically skilled workers, excellent network connectivity, and sustainable approaches to other requirements such as cooling. Just as the determination of the environmental impact of the cloud is not one-dimensional, when building cloud data centers we must consider several contributing factors, and not the power element alone.

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