Cloud computing—that is, a shared approach to computer resources, where software, storage, and information are provided to computers and other devices (such as smartphones) over the Internet—has the potential to help businesses reduce their carbon emissions. Or so says a new study, “Cloud Computing and Sustainability: The Environmental Benefits of Moving to the Cloud,” recently commissioned by Microsoft, Accenture and WSP Environment & Energy. The study concentrated on Microsoft’s cloud offerings, specifically, Microsoft Exchange, Microsoft SharePoint, and Microsoft Dynamics CRM. Each of those applications is available in the cloud, and “on-premise.”

The study found that, for large deployments, Microsoft’s cloud solutions can reduce energy use and carbon emissions by more than 30 percent when compared to their corresponding Microsoft business applications installed on-premise. The benefits are even more impressive for small deployments: Energy use and emissions can be reduced by more than 90 percent with a shared cloud service.

After all, a 2008 report (link opens PDF) estimates that “the potential impact of ICT (Information and Communications Technology)-enabled solutions to be as much as 15 percent of total global carbon emissions (or 7.8 billion tons of CO₂ equivalents per year)” and “the environmental footprint from data centers will more than triple between 2002 and 2020.” The study identifies four basic areas that drive cloud computing’s environmental advantages:

• Dynamic Provisioning—on-premise IT infrastructures typically over-allocate resources that site idle for some period of time, while cloud providers can manage capacity more efficiently.
• Multi Tenancy—cloud architecture lets providers simultaneously serve multiple users/companies on the same server infrastructure.
• Improved Server Utilization—“Whereas a typical on-premise application may run at 5 to 10 percent average utilization rate, the same application in the cloud may attain 40 to 70 percent utilization, thus dramatically increasing the number of users served per machine.”
• Data Center Efficiency—measured via a Power Unit Effectiveness ratio (PUE), or the ratio of total data center power that goes to power the IT hardware.

As I said, the study focused exclusively on Microsoft’s cloud computing solutions, but the same basic principles apply to any other cloud implementation. There is a danger, however, in assuming that as cloud computing becomes more prevalent, environmental benefits will scale proportionately. An increase in cloud capabilities may drive a greater user base—and thus a larger carbon footprint—than may have existed if computing was strictly limited to on-premise infrastructure. This is not to “dis” the cloud, of course; the benefits are there, but we should beware of unintended consequences.