Why UK data centres need to focus on optimal energy efficiency

The cheapest unit of energy is the one you don’t use. It’s an old adage, but one that has never been more accurate for energy intensive users looking to reduce bills. In this article, Jodie Eaton, CEO of Shell Energy UK, considers how IT and data centres can better streamline their power consumption, while working towards corporate decarbonisation targets and the ultimate goal of net-zero.

Volatility of the energy market has been one of the defining features of doing business in 2022. For some, this has proven an inconvenience. For energy intensive industries such as data centres, however, the picture is far more challenging.

Tightly managing overheads will not only prove key to success but, in some cases, survival. This requires intricate management of energy consumption and harnessing process efficiencies wherever possible to keep servers running and costs down.

But while market volatility is proving a challenge, regulation is also focusing the minds of data centre managers. While no longer strictly aligned to EU policy, the UK’s general direction of travel is towards big reductions in energy use, minimising carbon emissions wherever possible and transitioning towards net-zero.

Under the EU’s Green Deal, for example, data centres need to achieve carbon neutrality by 2030. This is likely to be echoed by any targets to come out of Westminster, once the new Conservative cabinet is in place. So, with regulation and market forces coming to a head in a way no-one could have predicted, how can the sector adapt?

Making a plan

Getting hold of statistics and reliable information on UK data centres is notoriously difficult – and work needs to be done here for policy makers to obtain a true picture of the sector and its energy consumption. One of the key areas for discussion concerns set points.

Traditionally, data centre set points for temperature have been 18 and 21°C (with specific ranges agreed for humidity). However, there has been no meaningful research to align these targets to meet other region’s targets. Most notable is the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE), which recommendations a temperature set point of between of 18-27°C and 8-80% RH for humidity.

Understanding how we measure energy usage is important, as it provides an agreed baseline. In the UK, data centres use Power Utilisation Effectiveness (PUE) to gauge consumption. This figure is based on the ratio of total facility energy divided by the amount of energy used to power the ICT systems and is expressed as a number.

Typically, data centres in the UK operate between 1.5 and 1.8, with the EU average being 1.8. In centres operating at a PUE of 2 and above, more energy is being used to provide the supporting infrastructure that is supplied to the ICT equipment. This suggests that more energy is being used to “cool” the infrastructure than is strictly necessary – so is a handy measure of efficiency.

The data centre estate

It is important for policy makers to understand the nature of the UK data centre ‘estate’. These operations come in all shapes and sizes, ranging from someone’s back bedroom to ‘hyperscale’ or cloud facilities, containing hundreds of thousands of servers. Due to huge demand, these types of facility are currently being built at a remarkable pace globally.

Latest estimates suggest that around such centres 500 exist globally with at least another 150 in construction. Most analysts estimate that data centre growth will be in the region of 25% for at least the next decade. Based on this thinking, we could soon see between five to 10 co-location facilities in every major city throughout Europe. A 2017 EU study indicated some 10,500 such facilities operating in the UK.

How to realise the “energy-saving potential”

From studies undertaken over the last five years or so, energy savings of at least 15- 25% could be achieved by data centres, with some businesses being able to achieve up to 70%. However, this would need a very radical approach, with businesses willing to make fundamental changes to their operations. Based on the figures above, typical server room energy bills could be reduced by around £10,000 - £25,000 per annum. And while this may not sound very much but multiply that by 80,000 (the estimated number of UK server rooms) and you achieve national savings of several million pounds.

How do I save, what do I need to do?

Firstly, the best option is for the UK to adopt the EU Code of Conduct for Data Centres (Energy Efficiency). This details more than 150 best practices that cover management, IT equipment, cooling, power systems, design, and monitoring of server consumption.

Secondly, the UK needs to obtain data on energy usage, how much of this energy is used by running cooling systems and how much uninterruptible power supplies use.

Moving ahead, data centres need to measure the amount of energy, and thus the cost being consumed, by their IT estate, to gain true visibility of current consumption. Next, the industry should calculate its PUE – the total amount of energy consumed by the entire facility, which then divided by the IT load. Given this key baseline, we can start to track progress. Implementation of best practise may be a challenge for some data centres, but there are lots of very credible training organisations out there to help with energy efficiency.

Exploration of options to contract renewable energy sources will also support decarbonisation goals whether this is through on-site generation, renewable energy supply contracts, or power purchase agreements. There are solutions that can be tailored to demand across both single and multiple sites.

Quick energy wins

Once you have the PUE covered and other monitoring processes in place, it’s time to start looking at reducing consumption. Many of the quick wins, in terms of greater energy efficiencies, are remarkably simple. Some operations run well established cooling systems which may be very inefficient in terms of energy use. Knowing your current PUE may provide you with new information that will help you make informed decision on issues such as cooling systems.

Likewise, real-time monitoring of energy use by site will enable anomalies to be quickly identified and dealt with.

Another option is the installation of occupation sensors that will automatically switch off lights in empty rooms and adjust heating levels in accordance with building use. Every small change can add up to making a big difference. It can ultimately free up cash to invest in more efficient equipment and embrace smart energy solutions. This is an approach that is gaining ever-more traction among manufacturers and data centres alike.

There is no single solution when it comes to optimising energy efficiency and every business will benefit from bringing in expertise to identify the steps it can take in both the short and long-term to bring their energy use under tight control. There is still a huge role that mitigation and reduction can play in preserving the competitiveness of the UK data centre sector.


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