It’s no news that energy usage is highly scrutinized nowadays. As we strive to cut use and increase the mix of renewables in generation, each industry in recent years has received some kind of “rating” by ecologically minded groups hoping that companies and industries that truly understand how much energy they use will take steps to reduce that energy.

Data centers are often portrayed as the black-hat villains of energy use. Statistics abound on the enormous amount of energy that data centers chew through. By most estimates, data centers use between about 1.3 and three percent of the world’s energy each year. By some reports, much of this power is wasted.

 A New York Times article from last year noted that most data centers use the vast amounts of energy they pull off the grid in a wasteful manner. Web services companies in particular run their facilities at maximum capacity 24 hours per day, regardless of demand. Because of this, many data centers are wasting as much as 90 percent or more of the electricity they pull off the grid, The Times found.

Some companies have taken steps to “go green.” Apple (News - Alert) now says that four of its data centers in North Carolina, Nevada, California and Oregon are powered by 100 percent renewable energy: a mix of solar power and hydrogen fuel cells. Facebook (News - Alert) – after being targeted by Greenpeace several years ago for its dirty energy consumption – has famously taken steps to build a new data center in Sweden that uses natural cooling and other technologies to reduce energy usage.

According to a new study, however, you can stop feeling overly guilty about using your laptop and desktop: it’s your wireless devices that are the guiltiest. The Centre for Energy-Efficient Telecommunications (CEET) has revealed that the biggest culprit of energy consumption in the cloud computing ecosystem is the equipment that facilitates wireless access to the cloud. CEET is a joint-venture between the University of Melbourne, Australia; communications vendor Alcatel-Lucent (News - Alert); and the Victorian (Australia) State government.

The group’s report – "The Power of Wireless Cloud" – says that the computing industry has underestimated energy consumption across the cloud ecosystem as more people access services with wireless devices such as smartphones and tablets. Wildly popular services such as Google (News - Alert) Apps, Office 365, Amazon Web Services (AWS), Facebook, Zoho cloud office suite, and many others delivered over wireless networks, are the real drivers behind energy consumption, according to Phys.org.

Cloud services over wireless networks are on a growth spurt, and the energy usage for these services are expected to spike 460 percent between 2012 and 2015 – the equivalent of 4.9 million new cars on the roads – according to the CEET, which says that wireless access networks (Wi-Fi and 4G LTE (News - Alert)) will be responsible for 90 percent of that energy. By comparison, data centers will use only a humble nine percent of that power.

"The findings of this paper are an important starting point to improving the energy efficiency of cloud services,” said Principal Research Fellow Dr. Kerry Hinton, CEET Deputy Director. “They provide a benchmark, highlighting where attention is needed and to measure progress to improvement."