Please enable JavaScript.  This webapp requires JavaScript to work at its best.

Does The Cloud Have A Green Lining?


[London, U.K.]  September 2021

How much thought have you put into reducing the carbon footprint of your IT estate? Do you offset, use a renewable energy provider or is the concept entirely new to you?

If you have thought about it, you may have decided upon a cloud migration strategy, and why not after all?  The top three players in the cloud all like to promote their green credentials.

Let’s take AWS for example, who commissioned research showing your carbon footprint can be cut by up to 88% (72% on average) if you move to the cloud – [source] How do they do this?  It’s a combination of more efficient hardware, utilisation, facilities and renewable energy.

Carbon efficiency of AWS infrastructure compared to surveyed US enterprises

Carbon graph

In my opinion, the reductions derived from the use of renewable energy are not what they seem.  If you are running instances in any of the AZs in the Europe (London) Region, these are going to be connected to the national grid so there is no way of guaranteeing that the power utilised is from a renewable source.

In actuality, Amazon are purchasing REGOs [source] but this doesn’t change the fact the energy used is no more or less renewable than that which powers your PC.  At the time of writing, the national grid derived 22.5% of its energy from renewables in the past month [source]

The 11% reduction from more efficient facilities may not seem high but we should never discount marginal gains as they add up. That said, the Uptime Institute’s 2020 Annual Survey shows that the average PUE of datacentres has not dropped significantly since 2013.  It’s worth reviewing the PUE of your current site, or potential future sites, but if you are in a new build facility the chances are you won’t realise this saving by moving to the cloud.

More efficient hardware and utilisation have the potential to bring significant reductions in your footprint. The fact that each new generation of hardware is more efficient than the last is a measured trend so in that respect, the simple expedient of purchasing new hardware will reduce your carbon footprint.  When it comes to utilisation, I think the reductions indicated from a move to AWS will not be easily realised.

Download the report

It appears the basis of the calculations rely on an estimated average server utilisation value of around 18% [source]. Whilst real world utilisation will vary considerably in my opinion, this is low.  That said, a review of your server estate and a more aggressive approach to consolidation of workloads can bring you savings.  If you accept the 18% value, then consolidating 3:1 will net a 66% reduction.

Although it may seem this article intends to dissuade you from migrating to the cloud, that is not the case.  Whilst I may disagree with the extent of the claimed reductions, my thoughts are that AWS has the ability to leverage economies of scale and purchasing power in the hunt for efficiency that most organisations will not be able to match.  Rather, the takeaway from this article is to understand the strategies that AWS employs to reduce IT carbon cost are as equally applicable to your existing estate.