From energy consumer to energy contributor: The emerging role of data center heat reuse

Data center growth is often framed as a competition for power, water, land, and infrastructure. Heat reuse offers a different proposition, where digital infrastructure can also supply part of the energy mix needed by communities and can offset fossil-based fuels that would otherwise be used for heating.

Nearly all electricity used by data center IT equipment ultimately becomes heat, which is typically rejected through the cooling system. Captured and redirected, this thermal energy can heat buildings, be integrated with thermal energy networks, reduce emissions, and transition data centers to community assets.

Rising computing density and the shift to liquid cooling, through techniques such ad direct to chip or immersion cooling, are making recovery of heat easier. These changes can make heat available at higher temperatures, which reduces the work heat pumps must do to bring it up to network supply temperature.

Cities, campuses, and utilities are electrifying heating systems and seeking reliable, no or low-carbon thermal resources. Because data centers generate heat continuously, they can provide a relatively predictable source for nearby buildings, municipal facilities, campuses, and district energy networks. Using recovered heat in place of conventional heating fuels can reduce emissions.

Heat recovery can also create benefits for the data center. Depending on configuration and how well recovery is matched to the heat load, heat reuse may reduce cooling tower water use and noise. Heat reuse is therefore more than just an environmental measure; it is a strategy that connects digital growth with wider community objectives.

In New York, Ramboll evaluated a system that would capture heat from a data center’s condenser water loop and use water-to-water heat pumps to provide heating for a large mixed-use building. The concept showed how heat recovery could reduce cooling-tower loads and reliance on steam-based heating without necessarily requiring a thermal energy network.

At a much larger scale, Ramboll served as Owner’s Engineer to Fjernvarme Fyn, which supported recovering surplus heat from a hyperscale data center in Odense, Denmark. Ramboll designed the heat-pump installation and energy center, supported tendering and construction, and developed the operating strategy. Large-scale ammonia heat pumps raise the recovered heat to 70–75°C, supplying approximately 45 MW to the district heating network and providing 35MW of cooling to the data center. The system recovers approximately 215,000 MWh annually, enough to provide heat to more than 12,000 homes.

The technologies are proven. What takes work is aligning data center operators, utilities, municipalities, developers, and heat users around technical requirements, investment, schedules, and commercial terms.

So what should developers do?

Plan for heat reuse from the start

The strongest opportunities emerge when heat reuse is considered before a data center site and cooling system are fixed.

Proximity to year-round thermal demand, recoverable heat temperature, network access, infrastructure routing, and commercial arrangements can determine whether a project is viable. Addressing these factors during site selection allows heat reuse to influence cooling design and infrastructure planning rather than becoming a retrofit challenge later.

This is particularly important as liquid cooling becomes more common. Warmer return temperatures make recovered heat more valuable, but only if the facility and the network are designed to use it, ideally with low-temperature networks that can accept it directly.

The key question is not simply whether heat can be captured. It is whether the right users, infrastructure, ownership/commercial structures, and development timelines can be brought together.

Use policy momentum to accelerate heat reuse

Policy is beginning to reflect this opportunity. The EU’s recast Energy Efficiency Directive requires data centers of at least 500 kW IT load to report energy and waste-heat performance annually, while facilities above 1 MW must recover waste heat unless technically or economically infeasible.

In New York, NYSERDA’s Heat Recovery Program funds data center waste heat reuse projects, and various NYSERDA funded studies examine integration with district energy systems.

In Quebec, the Programme de valorisation des rejets thermiques (PVRT) provides direct provincial support for waste heat capture and distribution infrastructure. Data centers are explicitly identified as a source of recoverable heat, and the PVRT program has awarded $40 million to Les Fraises de l’Île d’Orléans to capture and use waste heat from QScale’s Lévis data center for a nearby 12-hectare greenhouse complex. Notably, Canada has strong enabling conditions, via clean electricity, dense urban heating demand, and emerging district energy infrastructure, but still lacks the explicit Energy Reuse Factor mandates seen in Europe.

This policy momentum provides an opportunity to move heat reuse from a future consideration to a project requirement through engaging municipalities, utilities, and potential heat users early; documenting recoverable heat potential during planning; and using grants, reporting requirements, and emerging performance standards to build the commercial case. By aligning project design with policy direction, developers can reduce uncertainty, strengthen permitting narratives, and position data centers as contributors to local energy transition goals.

As data centers become a larger part of regional energy systems, their role can extend beyond computing. Heat reuse offers a tangible way to create shared value by turning an unavoidable byproduct into a local resource for decarbonization and community infrastructure.

The opportunity is not simply to find new energy sources, but to put energy already being produced to productive use.