The Greenest Computing Is Cloud Computing

Most things in life require energy. From the refrigerator and the microwave to the iPhone and the iPad; nearly everything we touch uses some form of embedded energy. Cloud computing is no different, except in one crucial respect: it’s the most efficient — and energy-efficient — form of computing yet invented.

This fact is worth keeping in mind amid the confusion spread lately by some writers who observe that cloud data centers consume lots of electricity and assume that’s a negative development. Rackspace uses 0.00081 percent of the world’s energy to deliver one of the most innovative and flexible cloud portfolios that provides social and economic benefits for over 180,000 customers.

Of the more than 7 billion people on the planet, 80 percent have access to electricity, 75 percent have cell phones and yet only 35 percent have Internet access. It’s an unprecedented time of global innovation and instantaneous knowledge sharing. Computing and data center companies continue to meet the demand to connect, communicate and exchange information. Innovations like the cloud are key to insuring that growth becomes more efficient.

Computing gets more efficient and specialists like Rackspace know how to do it best.

We at Rackspace think about sustainability in a holistic manner, and we want to share a few thoughts specifically about how we think about the power we use. We are specialists in driving infrastructure at scale. It’s at the core of our business.

Powering our business: every watt counts!

Rackspace is acutely aware of the cost of power. It’s one of our biggest expenses. We actively manage energy spending to drive value for customers and efficiency for our business. Every watt Rackspace uses is tracked — It came from somewhere (a power company, a generator) and it went somewhere (an office, a data center to power a server or power infrastructure). Understanding our power use helps us identify new ways to conserve resources – both natural and financial. Our Global Energy Team comprises sustainability, finance, sourcing and data center experts and sets the company strategy and policy focused on renewable energy, advocacy and efficiency.

 Investing in renewable energy

Rackspace purchases 25 percent renewable energy worldwide (and our UK data center and office are powered by 100 percent renewable energy). We evaluate existing and potential data center sites to understand our impact before we invest and built it into our long term plans. We evaluate sources of purchasing additional renewable energy and generating renewable energy to move more of our energy demand off the grid completely.


We continually take steps to improve energy efficiency and reduce consumption of other natural resources. Whenever possible, we select data centers in cooler climates and choose energy efficient facilities and hardware allowing us to deliver more computing performance per watt. Our recently announced data center in Australia will be among our most efficient.

When it comes to our product portfolio, our Global Infrastructure Team matches the expected workloads to the hardware and infrastructure build-outs to look at reliability and performance per watt. This approach drives efficiency throughout our operation — from building location and materials, HVAC, power distribution, containment, virtualization and compute performance per watt. Even the software that runs on machines makes each generation of computing more efficient. We expect our work with The Open Compute Project to yield additional benefits in this area going forward.

One thing that really has moved the needle for efficiency is virtualization. It lets us consolidate the work of many systems to function on fewer servers and delivers efficiencies in memory, hard drives and processors, as well as in power consumption. Our annual reports indicate that from 2009 to 2011 our total customers have grown by 90 percent but our number of servers has grown by only 41 percent.


Our advocacy strategy enables us to work with upstream partners and providers to continue to improve the long term outlook of reliable, affordable clean energy. We see it as a way to sustainably deliver value to our customers.

A word on generators

On-site generators provide important back-up power for our data centers, but part of our efficiency strategy is to NOT run them unless we need to. Given total costs to purchase, maintain, test and fuel them, generators are more expensive per KWH than purchasing power off the grid. They are a backup plan used by mission critical services in cities, hospitals and factories around the world in case they’re needed for short amounts of time. No one running a mission critical enterprise wants to be on backup power for very long. As a company, we track our emissions from power, generators, business travel and even the commute Rackers take to work. It’s all part of the bigger picture: emissions matter and continually driving down our intensity is an important business metric.  

Bottom line: Power is integral to our customers, we take it seriously and we manage it well.

P.S. Rackspace was also recently named to the 2012 Dow Jones Sustainability North American Indexes (DJSI), which rates the 2,500 largest companies in the Dow Jones Global Index based on economic, environmental and social performance. I’ll talk about that more in my next post.

Melissa Gray was Rackspace’s Senior Director of Corporate Social Responsibility. She was responsible for defining and guiding the company’s sustainability strategy and activities around the globe. She joined Rackspace in October of 2009. Her prior roles include the development of operational support systems and Chief of Staff to the CEO developing Rackspace’s multi-year strategic plan. Gray brought over 15 years of business strategy and operations experience to Rackspace. She has worked for a Fortune 10 company, transforming complex legacy businesses through innovation. She holds three U.S. and EU Software Patents. Melissa received her B.A. from Western Michigan University. Follow Melissa on Twitter @GreenRacker.


  1. Hi Melissa,

    Nice article – well written but I notice you managed to avoid mentioning Rackspace’s emissions anywhere in the piece.

    You need to publish some hard data to prove that “the Greenest computing is Cloud computing” – it is not enough just to say so.

    If an organisation has an in-house email server, I can relatively easily measure its energy utilisation, and from that calculate its emissions. If it moves to a Rackspace server for the organisation’s email, we now have no way of knowing its emissions. If you are not publishing them, for all we know, their emissions are significantly higher than they were when they were in-house.

    If, as you say, “Every watt Rackspace uses is tracked”, then it should be straightforward to report on energy use to your customers (my utility co. can do it). Will Rackspace do this? Or better yet, build the functionality into OpenStack, so all OpenStack users can do this?

    Btw, I assume your new data center in Australia was sited based on access to renewables?

    • Tom,

      First, I want to apologize for the ‘gremlin’ that caused the delay in the receipt and our response to your feedback. We try really hard to live our core value of transparency. I don’t know what happened, but I want you to know our intent is to be responsive. Thanks for reposting.

      We agree that publishing ‘hard data’ is the way to lead. Not all clouds are created equal and it’s through the sharing of information that allows customers and other stakeholders to make informed choices. We’ve been tracking our emissions for a couple of years now and are in the process of auditing that data for disclosure—likely to start with 2012 results disclosed sometime in 2013. Until that work is complete, I do want to share sources of publicly available data on our operations:

      -How Much We Spend On Power: Rackspace 2011 Annual Report Item 7A (2011 $22.4M; 2.2% of net revenue)

      -How Many Servers We Operate & MW Utilized: 3Q12 Quarterly Earnings Page 21 (As of 3Q 89,051 servers & 23.5 MW)

      – Energy Mix & Emissions: In 2011, we purchased 25% Renewable Energy; How Clean Is Your Cloud; Greenpeace 2011

      You touch on a topic I’m very passionate about—providing feedback to customers so they can understand the financial and environmental impact of their actions. Two weeks ago this was the topic I presented at GreenBuild (The Future of Efficient and Responsible Computing.) Providing this kind of ‘nutrition information’ to customers helps them do a thoughtful comparison. We’re working toward that disclosure. Please be patient with us.

      While we track every watt internally, it is not as straightforward as you’d like to think. Most of systems today are ‘closed’ and don’t talk to one another—we do some things that work internally for us, but aren’t dynamic enough for customers. We’ve been looking at the best way to move forward—either building it ourselves, or encouraging companies who already are experts at this technology to contribute this functionality to OpenStack and The OpenCompute project. No takers yet, but we think there is a real opportunity to capture mind and market share when this is solved. I hope you’ll continue to encourage others on this as well.

      This year we’ve been focused on re-launching our cloud portfolio on OpenStack—a gargantuan undertaking that has really gone well for us!

      Thanks for the plug for our newest data center ‘down under’. We’re excited about Australia opening in the first quarter of 2013. Access to reliable, affordable, clean energy is part of our data center siting model—along with access to network and a host of other operational needs. The Australia DC is located between the Smithfield (160 MW Gas) and Warragamba (50 MW Hydro) power plants. The building has also been designed to be highly efficient, leveraging free air cooling and a solid LEED rating.

      Thanks again for your post. I appreciate you taking the time to engage with us.


  2. The greenest thing about rackspace’s cloud is the money it gets them. Please… I understand it’s not just rackspace, but fake blogging articles for adverts is getting sickening.

  3. Hi Melissa,

    thanks for responding to my questions – and for providing some of the numbers around your power and emissions.

    As you noted though, transparency around the emissions your customers generate, by using your cloud platform, is what you should be aiming for. I understand it is not easy (I co-founded, built and open-sourced a hyper energy-efficient data center in Ireland in 2006-08), but little worthwhile is easy.

    If you need help with this, I’d be happy to work with you – I have a bit of experience in this space.

    Please feel free to reach out to me on email ( to discuss further.

    Btw, re your data centre ‘down under’ – what is the energy mix going into that DC and who is the provider?


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