AI Powers Campus Heating, Could Your Home Be Next?

In an innovative convergence of artificial intelligence and sustainable infrastructure, students at the Technological University of Dublin’s Tallaght campus are experiencing an unexpected benefit: their campus is being heated by the surplus warmth generated by a nearby Amazon Web Services data center.

Since 2023, this initiative has positioned the campus as a key beneficiary of a burgeoning trend in the Dublin suburbs, where waste heat from power-intensive data facilities is being channeled into district heating networks. Historically, the low-grade heat produced by data centers has posed a challenge for direct reuse in warming other buildings. However, the escalating demand driven by the AI revolution, which necessitates significantly more powerful and heat-generating computing infrastructure, is compelling operators to seek novel solutions that balance operational efficiency with environmental responsibility.

Adam Fabricius, commercial manager at HVAC provider Sav Systems and a researcher for its sister company EnergiRaven, highlights AI as a pivotal factor enabling this transformation. “The exciting thing is that AI can give you higher temperatures, and the water cooling makes it a lot easier. You need a lot less hardware to connect these systems,” he explained. This advancement not only makes waste heat more viable for district heating but also enhances the “social license” of data center operations, according to Brendan Reidenbach from the International Energy Agency. “It may not be ultimately very cost effective on paper, but it does contribute to that good social impact by turning what is a potential bad news story of increased data centers into a good-news story of what is ultimately decarbonized heat supply. So it’s very much a win-win situation,” Reidenbach added.

Ireland’s ‘Blank Slate’ for District Heating

Major technology firms are increasingly embracing such waste heat recovery strategies. Microsoft has announced plans to integrate its data center with the Høje-Taastrup district heating network in Denmark. Equinix is already supplying heat to 1,000 homes in Paris from one of its data centers, and Google has launched a significant heat recovery project at its facility in Hamina, Finland. These initiatives underscore a broader industry shift towards circular economy principles within the digital infrastructure sector.

Ireland, in particular, represents a unique landscape for these developments. The nation previously implemented a moratorium on new data center applications due to concerns over the strain on Dublin’s power grid, with data centers consuming a substantial 22% of the country’s electricity in 2024. However, as the AI boom gained momentum, sentiment shifted, recognizing the significant economic potential these facilities offer. Ireland’s easing of the moratorium late last year created an opportune moment for innovative projects like the Tallaght campus initiative.

Reidenbach characterizes Ireland as “effectively a blank slate” for district heating systems, given the nascent state of such infrastructure in the country. The Tallaght project serves as a prime example of the benefits derived from integrated planning, fostering collaboration between power system operators and distribution grid operators. In 2020, local authorities established Heat Works, Ireland’s first not-for-profit energy utility, which now sources 100% of its heat from the adjacent AWS data center. Rosie Webb, head of decarbonization at TU Dublin, confirmed the project’s impact: “While we are only in the second year of monitoring, we have evidence that the project has limited our exposure to market price shocks generally.” TU Dublin’s calculations indicate that the campus abated approximately 704 metric tons of carbon dioxide in 2024, even with the addition of two new buildings to the site. Niamh Gallagher, AWS country lead in Ireland, described the Tallaght data center as offering a “unique opportunity” for heat reuse, noting that AWS provides the recycled heat free of charge. The scheme was originally designed to heat 55,000 square meters of public buildings, commercial spaces, and 133 apartments, demonstrating a significant scale of environmental benefit. Gallagher emphasized, “It’s a win-win when we can identify a special project that uses our infrastructure to support the climate goals of the community.”

In the realm of heating networks, Europe generally holds a more advanced position compared to the United States, according to Ben Hertz-Shargel, global head of grid edge at energy research firm Wood Mackenzie. He suggests that medium-sized data centers situated closer to urban centers are particularly well-positioned to supply waste heat, citing Equinix as an example of a company that does not profit from this heat. However, scaling such models presents considerable challenges, including lengthy permitting processes and the substantial capital expenditure required for constructing new heat networks and integrating data centers.

A critical consideration is the lifespan discrepancy between district heating networks, typically designed for 30 years, and the rapidly evolving hardware within data centers, which have a lifespan of seven to 10 years. This mismatch poses a “very large risk of stranded assets,” as noted by Reidenbach.

Nexalus, a thermal engineering firm with patented technology developed at Trinity College Dublin, is at the forefront of innovative heat capture solutions. The company utilizes jet impingement liquid cooling to enhance chip performance while simultaneously capturing waste heat at higher temperatures. Kenneth O’Mahony, CEO of Nexalus, explained that their system delivers output at approximately 55 to 60 degrees Celsius without heat pumps, making the heat directly reusable for district heating. This contrasts with the typical 30 to 35 degrees Celsius of excess heat released by conventional data centers, which is far less practical for repurposing. Nexalus employs advanced chip-level heat mapping to target the hottest areas for precise cooling, akin to directing a showerhead. “We see data centers as energy borrowers, and actually as energy generating,” O’Mahony stated. “The desire should be that your data center is embedded inside the construction phase of cities, the design of the apartment blocks … producing enough heat for your entire building.”

This focus on optimizing heat recovery is gaining traction. Nvidia’s recent unveiling of its next-generation Rubin chips, which require less intensive cooling than previous models, has sparked industry discussion. Rob Pfleging, CEO of Nautilus Data Technologies, views this development positively, noting that it “allows now for the much easier reuse of that heat,” aligning with his company’s strategy of increasing water temperatures for greater efficiency.

Beyond Ireland, other regions are exploring similar data center heat reuse models. In October, U.K. officials visited Denmark to study the integration of data centers with district heating networks, aiming to replicate the Nordic country’s success. The U.K. has set an ambitious target to supply 20% of its national heating demand through heat networks by 2050, a significant increase from the current 3%.

Analysis by EnergiRaven and Viegand Maagøe suggests that by 2035, waste heat from data centers could potentially provide heating for at least 3.5 million homes, contingent on the parallel scaling of heat networks alongside AI infrastructure development. Matthew Powell, a researcher at EnergiRaven, argues that utilizing excess heat for community power effectively allows for the “double-use” of electrons. Fabricius further elaborated on the economic and geopolitical benefits: “Every kilowatt of energy we reuse, there’s a kilowatt of energy we don’t need to import.” This is particularly impactful when replacing natural gas for heating, as it directly contributes to decarbonization efforts and reduces reliance on volatile energy markets. “You’re using it once for the computation, and then you’re using the heat again to heat people’s homes that would have otherwise been generated from gas, if it was a boiler,” he told CNBC.

Regarding the potential risks of depending on a single private data center for a core utility, TU Dublin has stated that the Tallaght District Heating System is designed for diversification, with ongoing exploration into geothermal energy and plans to integrate various renewable sources. Currently, the scheme fulfills 92% of the campus’s heating demand and has significantly accelerated TU Dublin’s progress toward its 2030 decarbonization goals. Globally, district heating accounts for about 10% of building heat demand, with a substantial 90% still derived from fossil fuels. For countries like the U.K. to fully leverage waste heat opportunities, a transition away from gas and the development of appropriate infrastructure are paramount. Fabricius acknowledges the inherent difficulties, stating, “Diversifying systems is probably going to be the best way, but it’s going to be painful. It’s not going to be easy,” adding that the U.K., for instance, is now at a critical juncture where “we actually need to do something differently.”