Artificial Intelligence (AI) has surged to the forefront of UK innovation, but are we equipped with the infrastructure to support it?
In January, Prime Minister Sir Keir Starmer unveiled the government’s AI Opportunities Action Plan to harness the technology to boost economic growth and public service efficiency, with the broad objective of making the UK ‘one of the great AI superpowers’.
Central to this ambition is the expansion of data centres. Such growth presents significant challenges, however, including energy consumption, Grid capacity and cooling demands. At the same time, it also opens up opportunities for sustainable development and technological innovation.
Electricity demand
‘What we’re seeing is an increase in high-performance computing [HPC],’ says Malcolm Howe, partner at Cundall, leading the firm’s critical systems sector. ’The power density of our devices is rising dramatically, which is driving these changes in data centre function.’
The power demands of these facilities have skyrocketed. ‘When I entered the industry, data halls with 700kW of equipment were a reasonable size. Now, we’re routinely designing data halls with 10MW of kit, and hyperscalers have started talking about GW campuses,’ says Howe.
In September 2024, the National Grid’s chief executive, John Pettigrew, cautioned that AI-driven energy consumption could increase sixfold in the next decade, raising the UK’s energy demand by 500%.
‘It’s a double whammy from an energy point of view,’ warns Howe. ‘Not only do the servers demand significantly more energy, but the cooling systems needed to regulate temperatures also consume substantial power. It’s becoming increasingly less energy efficient.’
Asad Kwaja, associate director, district energy and low carbon infrastructure, at Aecom, highlights the limitations of the UK’s National Grid. ‘One of the big barriers is the constraints around power use and these large centralised demands,’ he says.
The Oxford-Cambridge Arc, a designated growth zone with strong academic and research ties, has been identified as an area for data centre expansion in the government’s AI drive.
Arup director Gareth Williams believes that ‘while there’s an aspiration to concentrate development in one area, the power demands are likely to place limits on how concentrated this can really be. We’d benefit from taking a more holistic and strategic view.’
AI could increase the UK’s total electricity demand by 500% in the next decade
Howe agrees. ‘Where you put a data centre is governed by multiple factors – power supply, fibre connectivity and water availability. There is an evident lack of understanding of these tick boxes,’ he says.
To alleviate the pressure of increased energy demands, Kwaja highlights an opportunity to develop data centres in areas with surplus renewable energy, such as Scotland, where wind power is abundant. However, Howe believes that renewables alone won’t suffice.
One potential solution could be onsite nuclear generation, and some facilities in the US are exploring the use of small modular reactors to support a net zero hyperscale data centre. But this isn’t a solution that can be replicated for all data centres, Kwaja advises. ‘It’s important to keep in mind that building a data centre is complex and expensive enough,’ he says. ‘Adding a reactor alongside is another huge project in itself. Its perhaps underestimated how difficult that would be to locate and deliver.’
Cooling challenges
The shift towards AI-centric data centres has led to design modifications, particularly in cooling infrastructure. Traditional data centres rely on hot- and cold-aisle configurations, where air passes through server racks to carry heat away. However, Howe explains that the increase in airflow required to cool high-power racks has led to forceful gales in cold aisles, necessitating wider rack spacing.
‘As a result, despite the higher power of individual racks, the overall power density per square metre of the data hall remains the same because of the reduced number of racks and increased spacing,’ he says.
‘This means we’ve passed the point where it’s sensible or efficient to cool servers using just air. Direct liquid cooling to the chip is becoming essential,’ Williams adds.
‘We are also drastically reducing the opportunity for free cooling. You’re introducing more mechanical cooling during the peak summer period, and that is impacting power usage effectiveness [PUE],’ Howe says.
The power density of our devices is rising dramatically, which is driving these changes in data centre function
PUE is the ratio of energy used by a computer data centre facility and the energy delivered to computing equipment, with a low PUE indicating better efficiency. ‘We’re seeing PUE stats creeping back up for the first time in years. From a sustainability perspective, that’s a big problem,’ warns Howe.
Innovation in cooling systems is crucial for sustainable design. In one project, Williams describes how Arup helped the client implement an advanced cooling strategy using thermal energy storage tanks based on water stratification. ‘By leveraging water’s density properties, hot and cold water is naturally separated,’ he says. ‘We used computational fluid dynamics to design inlet and outlet diffusers, ensuring steady water flow and effective temperature stratification for efficient cooling.’
Heat recovery
A key solution for reducing carbon impact and improving sustainability is residual heat reclaim. Williams notes that Germany was the first European country to make the reuse of waste heat mandatory when it implemented the Energy Efficiency Directive through the Energy Efficiency Act (2023).
Howe believes it’s vital that the huge amount of heat that data centres produce is captured and re-used: ‘This heat can displace burning fuel somewhere else.’ Kwaja agrees: ‘Wherever there is an opportunity, heat recovery should be encouraged.’
A prime example of waste heat recovery is in Odense, Denmark, where Meta’s data centre, designed by Cundall, recovers 45MW. This is transferred to ammonia heat pumps operated by the local energy services company, supplying hot water to a district heat network that covers the whole city. ‘Generally, when connecting a data centre to a heat network, for every megawatt you might be able to deliver heat to 1,500 to 2,000 homes,’ says Kwaja.
‘Domestic heating is one of the major sources of fossil fuel consumption in the UK,’ states Howe, who highlights challenges in the UK, where district heating infrastructure is lacking. Denmark’s success stems from a diverse mix of energy sources and users, balancing seasonal demand. ‘It works really well in Denmark because of its scale, and the different types of customer and, therefore, different load profiles,’ says Howe.
‘District heat networks tend to want the most heat in the winter, when it’s cold, whereas data centres work at their most energy efficient in the winter, when they can make use of free cooling. Peak summertime is when a data centre rejects the most heat, so you want to be connected to industrial plants or sports centres that are going to use it all year,’ says Howe. (See the Open project here)
Williams agrees, and says the investment needed to connect the right consumers presents a challenge. Kwaja, meanwhile, hopes that a big policy drive on heat network zoning will aid this, and encourage the uptake of heat networks across the country.
‘We need to be better at forward planning. Between the growth of networks and data centres, there’s a real opportunity to harness the synergies between both, he says.’
Future-proofing
In September, technology Secretary of State Peter Kyle announced that data centres are now categorised as critical national infrastructure, essential for the wellbeing of society. However, a report from trade association techUK, Future-proofing digital infrastructure: Climate resilience in the data centre sector, warns that data centres are at increasing risk of heatwaves, flooding and power outages because of climate change.
Legacy data centres are at significant risk, often ill-equipped to manage rising data demands and technological developments, says Williams. ‘Without adequate attention, this could result in spiralling operational costs, inability to support increased power densities, failure to meet sustainability requirements, and challenges with energy accessibility.’
The UK Net Zero Carbon Buildings Standard provides specific guidelines for data centres. While new-build data centres are exempt from its general energy demand limits, they must meet all space-heating demands through heat reuse within the facility.
‘We’ve got to get there somehow, otherwise we’re going to bake the planet,’ says Howe. ‘Necessity is the mother of invention.’
Williams agrees, and is hopeful. ’The scale of next-generation data centre campus developments creates opportunities to do things differently,’ he says. ‘It’s an exciting time to be working in the data centre business.’
