The UK has more data centres than almost any other country with much more growth predicted, each of which generates incredible amounts of waste heat. By building heat highways to harvest this sustainable resource – and planning data centres in “Green Energi Havens” – we can unlock clean, lowcost heating for millions of homes.
A stark reality we need to accept in the UK is that our days of cheap gas heating are over. Due to our dependence on this polluting fossil fuel, skyrocketing inflation, and geopolitical conflicts, this once affordable source of heat is now, for many people, a financial burden. There are around 6.5 million UK homes in fuel poverty, and with gas prices expected to rise even further, millions more are teetering on the edge of this precarious financial cliff.
Another uncomfortable truth is that renewables alone can’t fix our heating woes. While we continually install more wind turbines, we also spend billions of pounds curtailing their electricity generation because our antiquated grid can’t cope. Coupled with the rising power demands of mass electrification, automation, and EV charging, it’s clear that heating (through the mass utilisation of individual heat pumps) is not the best use of this precious green resource.
To lift millions out of fuel poverty and achieve our net-zero target, we need to foster a sustainable economy where nothing goes to waste. A critical first step is utilising the clean and abundant waste heat we already produce – most of which currently vanishes into thin air. And, as is often the case, some of our largest waste heat producers are hidden in plain sight: commercial data centres.
Turning Big Data into Green Heat
Data centres are the backbone of the digital economy, powering everything from email and streaming platforms to industrial cloud services and advanced AI models. These warehouse-style facilities often house thousands of computer servers and, as a result, consume staggering amounts of electricity. According to the International Energy Association (IEA), data centres (including those for cryptocurrency and AI) consumed around 460 terawatt-hours of electricity in 2022, or almost 2% of the world’s entire power supply. And with new AI data centres requiring up to ten times as much electricity as cloud computing facilities, the IEA projects these figures could more than double by 2026. National Grid Chief Executive, John Pettigrew, has forecast that to power those data centres, electricity use would increase six-fold in the next decade.
We now have over 500 data centres in the UK, making us the world’s third-largest market behind the US and Germany. Most are located in and around our largest cities: London, Manchester, Slough, Leeds, Glasgow, Aberdeen, Edinburgh, Birmingham, Liverpool, and Newcastle. But while this rapid proliferation has been a boon for big tech companies, they’ve released hundreds of these ‘energy hogs’ into the wild that strain the power grid and drive up electricity prices – yet give very little back to our local communities.
With many more data centres on the way, we need to use their geographical locations and waste resources to our advantage. The key to success is building ‘heat highways’ to transport their waste heat to our homes and businesses – and turn these titans of consumption into green heat producers.
A recent development is the advent of distributed data centres. These deliver data processing from small data centre nodes that can be located in buildings (leisure centres, care homes etc) with a large heat demand of over 100kW (this equates roughly to heating a 25m pool). They can also integrate with heat networks.
Delivering Clean Heat to the Masses
Heat highways are long-distance underground piping systems that are fast to build and can operate reliably for over 40 years. They use heat exchangers to convert waste heat into hot water, which they can then feed into district heat networks via thermal stores in our large population centres. Each connected dwelling features a boiler-sized heat interface unit (HIU) that transfers the supplied hot water into its space and water heating systems.
Unlike our polluting and expensive national gas network, heat highways are heat source agnostic. They can utilise renewable energies, commercial heat pumps (both large-scale and modular), geothermal heat from aquifers, combined heat and power (CHP) and energy from waste (EfW) plants, as well as waste heat from sources such as power stations, wastewater treatment plants, distilleries, abattoirs, and industrial bakeries. This diversity of heat supply can ensure district heat networks deliver the cheapest and greenest heat available all year round.
Heat Capture Legislation and ESG Impacts
With the UK striving to reach net zero by 2050, waste heat capture is critical to our clean energy goals. The EU recently adopted new legislation to rate the environmental performance of data centres, including their reuse of waste heat. UK companies that fall under the EU’s Corporate Sustainability Reporting Directive (CSRD) must now compile and publish transparent sustainability data.
For facility owners, heat offtake agreements support decarbonisation and ESG progress while reducing the Scope 3 emissions of British companies using their services. Over time, both the UK and EU are expected to increase the minimum requirements for data centres regarding their energy efficiency and reuse of waste heat. Ultimately, whether it’s driven by legislation, market forces, or public pressure, British data centres will need to embrace sustainability to remain globally competitive.
The European Commission suggests that all data centres of more than 1 MW should perform a cost benefit analysis to investigate whether the excess heat can be used in the district heating supply.
Building on Proven Heating Success
While the UK is only just realising the potential of data centre waste heat, many European countries already benefit from this valuable resource. In Stockholm, Sweden, around 10,000 apartments receive waste heat from a local data centre through a partnership with Stockholm Exergi. In the future, the city aims to meet 10% of its total heating demand (representing around 80,000 customers) from data centres. Further south in Odense, Denmark, one of Facebook’s hyper-scale data centres supplies waste heat into the city’s district heating network, covering the heating demand of around 11,000 homes. In Frankfurt, Germany, multiple projects are underway to utilise waste heat from its local data centres. The city estimates that by 2030, they could supply enough waste heat to service all of its private households and office buildings.
Here in the UK, there’s an incredible opportunity taking shape in outer London. The East Havering Data Centre is a proposed £15 billion project that will be the largest of its kind in Europe, featuring clusters of hyper-scale data centres. With a total electricity consumption of a staggering 650 megawatts, the proposed campus will also generate enough waste heat to supply over 300,000 homes. Connecting the site to a heat highway and converting the surrounding suburbs to district heating would secure significant volumes of clean, low-cost heat while directly progressing our net-zero ambitions.
The Best of British Innovation: Green Energi Havens
For the UK to achieve a diverse and reliable green heating supply, waste heat capture must become a core criterion of where and how new data centres are built. For example, in the last few years alone, National Grid spent billions of taxpayer pounds curtailing wind farms that were producing more clean energy than our grid could utilise. However, by co-locating new data centres near green electricity production – and connecting them to heat highways – we can create synergies that unlock the full potential of British energy.
Repurposing our old industrial sites into ‘Green Energi Havens’ can foster a sustainable economy where nothing goes to waste. These innovation hubs can use renewable energy to power data centres, produce green hydrogen, and support emerging industries such as e-fuels, green plastics, and carbon neutral fertilisers. Training facilities can be incorporated to foster green jobs and to retrain individuals currently working in the oil and gas sector. When Green Energi Havens are located near our major cities, Heat Highways can capture their waste heat and supply it to district heat networks, reducing costs and emissions for thousands of homes.
Turning Waste Heat into Sustainable Progress
With fuel poverty at crisis levels, energy security at risk, and a net zero target rapidly approaching, our reliance on natural gas is unsustainable in every sense of the word. If we want to make UK heating clean and affordable, using waste heat from data centres isn’t just a great idea – it’s a necessity.
With many new sites in development, prioritising waste heat capture will ensure these power-hungry behemoths deliver tangible community benefits. Through smart investments in Heat Highways and district heating, the UK’s digital prowess can also drive social and environmental prosperity.