Students at Dublin’s Institute of Technology are reaping the unexpected benefits of artificial intelligence. Artificial intelligence is helping heat the campus.
Since 2023, Dublin Institute of Technology’s Tallaght campus is one of a growing number of buildings in the city’s south-west suburbs to be heated with waste heat from nearby Amazon Web Services data centres.
Data centers have always generated excess heat, but integration with district heating networks has been slow because waste heat from power-hungry facilities is typically too cold to directly heat other buildings.
That is now changing. With the AI boom in full swing and data centers increasingly filled with racks of advanced chips that require three times as much computing power as before, operators have had to find new ways to maximize efficiency without sacrificing sustainability.
It’s a “twist” that makes AI more appealing, said Adam Fabricius, commercial manager at heating, ventilation and air conditioning provider Sav Systems and thermal networks researcher at its sister company EnergiRaven.
“What’s interesting is that AI increases the temperature, and water cooling makes it much easier. You need much less hardware to connect these systems together,” he told CNBC.
Brendan Leidenbach of the International Energy Agency told CNBC that supplying heat to district heating networks gives data centers “an additional social license.”
“Although in theory it may not be very cost-effective in the end, it contributes to a positive impact on society by turning potentially bad news of more data centers into good news of ultimately decarbonized heat supply. So this is very much a win-win situation,” he added.
Ireland is a “blank slate”
We’re seeing quite a bit of adoption among Big Tech. microsoft Announces plans to supply fuel to Denmark’s Høje-Taastrup district heating network. of Equinix The data center heats 1,000 homes in Paris. and google announced a large-scale heat recovery project at its facility in Hamina, Finland.
Ireland was one of two European countries to implement a moratorium on new data center applications, as power-hungry facilities strain Dublin’s power grid and will consume 22% of the small country’s electricity by 2024. Ireland eventually eased its moratorium late last year as the AI boom improved sentiment around the economic potential of facilities.
The IEA’s Mr Leidenbach said Ireland was “virtually a blank slate” as it had never had a district heating system in place. He said the Talaat plan shows the benefits of integrated planning as it brings together power system operators and distribution network operators.
In 2020, local authorities established Heatworks, Ireland’s first not-for-profit energy company. Waste heat from nearby AWS data centers provides 100% of the heat to the network.
“Although we are only in the second year of monitoring, there is evidence that the project is generally limiting its exposure to market price shocks,” Rosie Webb, head of decarbonization at Dublin Institute of Technology, told CNBC in an email.
Dublin Institute of Technology calculations show that the campus saved around 704 tonnes of carbon dioxide in 2024, despite the energy demands of two new buildings added to the site.
AWS’ data center in Tallaght offers a “unique opportunity” to reuse heat, said Niamh Gallagher, the company’s country leader. The scheme, in which AWS will provide free recycled heat, was originally intended to heat 55,000 square meters of public buildings, commercial space and 133 apartments, an area three times the size of the city’s Croke Park stadium.
“It’s a win-win if we can identify special projects that leverage our infrastructure to support the community’s climate goals,” Gallagher told CNBC.
keep hot chips cold
Ben Hertz Schergel, global head of grid edge at energy research firm Wood Mackenzie, said Europe is much more advanced than the United States when it comes to heating networks.
Hertz-Schagel said some medium-sized data centers near large metropolitan areas are likely to be in the best position to provide waste heat. He added that Equinix, which, like AWS, does not profit from the waste heat it supplies, is one example.
However, permitting delays and high capital costs for building thermal networks and integrating them into data center systems make scaling the model difficult.
There is also a life cycle mismatch. According to Leidenbach, district heating networks typically have a lifespan of 30 years, but equipment in data centers only has a lifespan of seven to 10 years. “That leaves a very large risk of assets being stranded,” he added.
We think of data centers as both energy borrowers and actually energy producers.
Kenneth O’Mahony
Nexus CEO
Nexalus, a thermal and scientific engineering company that patented the technology from Trinity College Dublin in Ireland, has researched ways to capture heat from the hot GPUs and CPUs housed in data centers.
The company uses jet impingement liquid cooling to improve chip performance while capturing waste heat at much higher temperatures. Nexalus CEO Kenneth O’Mahony told CNBC that the system does not produce “low-grade” heat, but delivers an output of about 55 to 60 degrees Celsius without the use of a heat pump. This is high enough that it can be directly reused for district heating, he said.
Other data centers typically emit excess heat at around 30 to 35 degrees Celsius, making reuse much less practical, the company said. It also maps the heat emitted by the chip, allowing it to target the hottest areas for cooling.
“It’s like a shower head in the shower. If you have pain in your shoulder, you point the head where you want it to go. That’s our job, and we plan to maximize the impact on each individual chip,” O’Mahony said.
“We think of data centers as both energy borrowers and actually energy producers,” he added. “The hope is that during the construction phase of cities, data centers will be embedded within the design of apartment buildings to generate sufficient heat throughout the building.”
Nexalus isn’t the only company exploring this technology. Nvidia The company recently announced its next generation Rubin chips, which don’t require as much cooling as previous models, causing alarm in the cooling market.
Rob Fregin, CEO of modular liquid cooling company Nautilus Data Technologies, said Nvidia’s announcement gave him “chills” because the company has long focused on raising water temperatures to enable “significant efficiency gains.”
“The great thing about[NVIDIA’s]announcement is that[it’s]a step in the right direction, because it will make it easier to reuse that heat,” Pfleging told CNBC.
Future challenges
Cities outside Ireland are also considering adopting a similar model. British officials visited Denmark in October to see how data centers are connected to district heating networks and learn from the Nordic countries’ successes. The UK wants to expand its heat network to reach 20% of the country’s heating demand by 2050, up from 3% currently.
According to analysis by EnergiRaven and Danish energy consultancy Viegand Maagoe, waste heat from data centers could provide enough heat for at least 3.5 million homes by 2035 if thermal networks are expanded in parallel with AI infrastructure.
Matthew Powell, a researcher at EnergiRaven, argued that by using surplus heat to power local electricity, we could effectively use electrons twice.
“For every kilowatt of energy we recycle, there is one kilowatt of energy we don’t have to import,” Fabricius said, adding that replacing natural gas with natural gas would make even more geopolitical and economic sense.
“Once you use it in your calculations, you’re using heat that would otherwise be produced from gas in a boiler to heat people’s homes again,” he told CNBC.
When asked about the risks of relying on private data centers for core energy supplies, UT Dublin said the Tara district heating system does not rely on a single power source. The university is conducting research into geothermal energy and plans to incorporate a range of renewable sources to further diversify its energy mix.
Despite this, the scheme currently meets 92% of the campus’s heating needs, and the university says it has significantly accelerated progress towards UT Dublin’s 2030 decarbonization target.
District heating currently supplies around 10% of the world’s building heat demand, with 90% of that total coming from fossil fuels. For countries like the UK to take advantage of waste heat reuse, they need to move away from gas and put the right infrastructure in place above ground, EnergiRaven’s Fabricius said.
Diversifying the system “would probably be the best thing to do, but it’s going to be painful. It’s not going to be easy,” Fabricius said, but Britain, for example, is at a stage where “we actually need to do something different.”
