Cloud service providers have previously drawn ire from environmentalists for not being transparent when it comes to the energy efficiency of their data centres.
However, a new report from the University of Melbourne in Australia says that the real sustainability threat comes not from the growing demand for data centers to house cloud-ready infrastructure, but from the rising use of cellular and Wi-Fi networks to access cloud services.
A 2012 report produced by Greenpeace titled "How Clean is Your Cloud?" argues that three of the biggest businesses delivering cloud-based offerings—Amazon, Apple, and Microsoft—are "rapidly expanding without adequate regard to source of electricity, and rely heavily on dirty energy to power their clouds."
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It sounded a warning over the growing demand for data center space (and consequently energy consumption) driven by cloud adoption. The report cites an estimate that nearly US$450 billion was being spent annually on new data center space and that data center demand was consuming 31 gigawatts of electricity, with an increase of 19 percent in 2012.
However, by 2015, the energy used to run data centers will be a "drop in the ocean" compared to the wireless networks used to access cloud services, said Dr. Kerry Hinton, deputy director of the Centre for Energy-Efficient Communications, the University of Melbourne-based research organization that produced the report.
"There is a significant emerging convergence between cloud computing and wireless communication, providing consumers with access to a vast array of cloud applications and services with the convenience of anywhere, anytime, any network functionality from the device of their choice," states the report, "The Power of Wireless Cloud."
Wireless energy demands increase
This "emerging convergence" has big implications for the energy consumption associated with cloud services, including cloud-based applications and storage. The report predicts that by 2015 energy consumption associated with the "wireless cloud" will reach 43 terawatt-hours, compared to 9.2 terawatt-hours in 2012.
"This is an increase in carbon footprint from 6 megatons of [carbon dioxide] in 2012, up to 30 megatons of [carbon dioxide] in 2015," which is the equivalent of an additional 4.9 million cars on the road, the report states.
Data centers will comprise only 9 percent on this increased energy consumption, compared to up to 90 percent for wireless access.
"The trend towards wireless is the real problem, and the networks are to blame," Hinton said. "Industry needs to focus on the real issues with wireless network technologies if it wants to solve this problem ... We often think of bandwidth as the barrier to the way online services evolve and improve. The very real message here is that the real bottleneck, looming sooner than we think, may be energy."
"To ensure the energy sustainability of future wireless cloud services, there needs to be a strong focus on the part of the ecosystem that consumes the most energy: wireless access networks," the report concludes.
This story, "Green tech: Wi-Fi, not storage, is the power hog, researchers say" was originally published by Computerworld Australia.