Research by a group of academics in Australia has revealed that datacentres only account for nine percent of the cloud's overall environmental footprint.
The report, titled The Power of Wireless Cloud [PDF] and released by Alcatel-Lucent's Bell Labs and the University of Melbourne, points out that wireless access network technologies account for 90 percent of the overall cloud energy consumption, using up 10 times more power than datacentres.
"Previous analysis and industry focus has missed the point: access networks, not data centres, are the biggest threat to the sustainability of cloud services," write the authors from the Centre for Energy-Efficient Telecommunications (CEET), based at Melbourne University.
"This is because more people are accessing cloud services via wireless networks. These networks are inherently energy inefﬁcient and a disproportionate contributor to cloud energy consumption."
"The network itself, and speciﬁcally the ﬁnal link between telecommunications infrastructure and user device is by far the dominant and most concerning drain on energy in the entire cloud system," the report argues.
The authors expect total energy consumption of the wireless cloud to reach between 32 terawatt hours and 43 terawatt hours in 2015, producing 30 megatons of carbon dioxide or roughly the equivalent of the carbon emissions from 4.9 million automobiles. The model for calculating these figures takes into consideration projected energy consumption by mobile-access networks (4G LTE), local (WiFi home and hotspot), data centers and the metro and core networks that connect all of the above.
The carbon consumption preditions are based on the assumption that wireless cloud networks will transfer and process between 2.2 exabytes and 4.3 exabytes of monthly traffic in 2015. The estimated user count is based on data by ABI Research and Infonetics and traffic-volume forecast projections by Cisco, Alcatel-Lucent, Nokia Siemens Networks and Ericsson.
The CEET study was published in response to a Greenpeace report that came out last April called How Clean is Your Cloud, which focused heavily on the power consumption of datacentres operated by major cloud service providers, while also identifying the percentage of that power sourced by renewable electricity.