In a report published this December, Pike Research has estimated the total green impact of this shift to the cloud that Koomey (and others) anticipate. According to Pike, not only are the energy efficiency improvements of cloud computing substantial, but growth in the cloud market (CAGR of 28.8% for cloud worldwide between now and 2015) will have important implications for both energy consumption and greenhouse gas (GHG) emissions: by 2020, the adoption of cloud computing will produce a 38% reduction in worldwide data center energy expenditures as compared to a business as usual (BAU) scenario for data center capacity growth. As senior analyst Eric Woods explains, “Few, if any, clean technologies have the capability to reduce energy expenditures and GHG production with so little business disruption. Software as a service, infrastructure as a service, and platform as a service are all inherently more efficient models than conventional alternatives, and their adoption will be one of the largest contributing factors to the greening of enterprise IT.”
This view of the cloud as a next stage in the evolution of computing efficiencies, which begins with virtualization and results in higher server utilization rates and reduced energy consumption, is not without its detractors. Katie Fehrenbacher
, for example, who writes on GigaOm, has cited findings from research conducted by Rod Tucker of the University of Melbourne which argues that consideration of the energy consumed by data travelling on the network between the cloud and a user’s device has been neglected in most cloud efficiency calculations and should be taken into account for certain applications. Tucker and his team have argued that in the case of storage, for example, energy-efficiency gains are negated when downloads from a public cloud service reach a certain threshold. Similarly, Greenpeace is no fan of cloud computing, taking the position in a recent report
that the huge data centres needed to support the cloud service delivery model are having a negative impact on climate change. Driven by profit motive to source the most inexpensive sources of electricity, Greenpeace argues, these “industrial-scale consumers of electricity” most often opt for “brown” as opposed to “green” sources of energy, and estimates of their carbon emissions impact inform a good portion of the report analysis – the impact of energy consumed through more traditional computing infrastructures (in the case of no cloud) curiously absent from the equation.