How Green Is the Cloud?

Txchnologist, NOVEMBER 7TH, 2011, BY MORGEN E. PECK

Think cloud. Now think rain. Now think spring. Now think green.

Now think again.

The term “cloud computing” may create associations of environmental harmony, but just like real clouds, cloud services are unpredictable, difficult to quantify, and prone to sudden bursts of growth and activity. These qualities have researchers and even some advocates questioning how green cloud computing is and how green it can be. The answer seems to depend almost entirely on how we use it.

Cloud computing is efficient in concept. Companies that once had to provide all the infrastructure for their computing and storage needs can now shift the load to service providers. Businesses are beginning to keep documents and email in the cloud and access them with software that they no longer have to own. When all of this work moves into the cloud, it gets consolidated by companies like Google and Microsoft that have spent many years optimizing their data centers to be energy efficient. These massive investments in efficiency will result in data center energy consumption being cut by one-third by 2020, according to the green tech analyst firm Pike Research.

New road, more cars

“What used to sit on a single sever is now being shared at a multi-tenant environment,” explains Reuven Cohen, the founder of Enomaly, a Toronto based company that develops products for cloud service providers.

But then Jevons’ Paradox comes into play: when you build a new road, it usually brings more cars. “The more resources you have, the more resources you use,” said Cohen. “That’s the nature of what technology is.” He argues that cloud computing as an approach is probably more efficient, but it encourages companies to take on even more computing, which ultimately leads to increased power consumption.

Others see a deeper problem. Kerry Hinton, an electrical engineer at the University of Melbourne, and a member of ARC Services Research Network, says that calculating efficiency is extremely complicated, and most people forget a key part of the equation.

It’s not a simple matter of adding up the load in a private network and transferring it to a consolidated data center. Once a company moves all of that information offsite, its employees have to go through the Internet every time they need access, and those operations consume energy too. The data may be traveling on superhighways, but it has further to go. “The thing that’s going to kill us in the longer term is connecting into the internet to talk to the cloud provider,” says Hinton.

Energy hungry routers

Consider how much more power goes into connecting to the Internet when an employee updates a spreadsheet using software from the cloud rather than a desktop program. Every time the page refreshes or the document gets saved, the employee may be communicating with multiple data centers around the world, hopping across an average of 12-14 routers, according to Hinton.

Hinton argues that routers are actually the greediest units in the Internet, gobbling up 7-10 nanojoules of energy per bit (for some perspective: there are about 4 billion nanojoules in a calorie.) Those crumbs add up quickly. And when customers make the connection wirelessly — a much more energy intensive data connection — their energy expenditure skyrockets, making the transportation of data an even bigger part of the efficiency equation.

Cloud computing could potentially reduce power consumption, says Hinton, but not while providers ignore this issue. Their services especially appeal to new businesses that are looking for ways to accommodate sudden growth without having to burn a lot of money on equipment. And there is a seductive pitch for this kind of customer: Dress your employees with low cost, low intelligence devices that can then connect to a highly sophisticated cloud anywhere, at any time.

Unfortunately, this is probably the least energy efficient implementation of cloud services, as it drives up wireless usage. “Cloud services can be green if you develop it correctly and you use it correctly. But business models have been put out there that are the opposite of that,” says Hinton. Companies could reduce power consumption by reigning in mobile access to shared documents and limiting how often they access cloud services over a wireless connection.

Although some improvements can still be made to routers and the actual infrastructure of the Internet, the efficiency of the cloud will fluctuate most with human behavior. It seems that whether computing goes green depends less on the cloud than all of the people standing beneath it.

Morgen E. Peck is a contributor to IEEE Spectrum, Innovation News Daily and other publications. Her last story for Txchnologist looked at “Skywalker” prosthetic technology.

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