Insights from EUSEW 2024: The potential of waste heat for decarbonisation



Heating and cooling


The European Sustainable Energy Week (EUSEW) presents an opportunity to exchange and discuss, each year, the hottest topics in sustainability and the green transition.

The session No Hot Air: The Potential of Waste Heat for Decarbonising Industry, Cities, and Buildings discussed the hot topic of waste heat and the role it can have in energy efficiency and the decarbonization of industry, cities, and buildings.

The session began with an introduction by moderator Pauline Lucas (Euroheat and Power) who started by emphasizing that waste heat is not a buzzword and has huge potential to transform the heating and cooling sector and help Europe become carbon neutral and achieve energy independence. Heating and cooling are a big part of the energy transition and currently, both sectors are largely driven by fossil fuels. Transforming the industry requires circularity and energy efficiency: we should exploit all opportunities to tap into this huge potential of waste heat, especially as waste heat sources are local and ready to be used in neighbourhoods and businesses.

What are some of the challenges to waste heat recovery?

  • Policy and regulatory framework
  • Stakeholder’s awareness (city, industry, operators, national….)
  • Business models (risks and costs)
  • Technical and skill obstacles

Examples of waste heat recovery

The session presented some inspiring success stories where waste heat has been recovered. Speakers from industry, including representatives from Xylem, Danfoss and Trane Technologies presented the innovative solutions that already exist that are driving innovation in the heating and cooling sector.

First to speak, Xylem, a company working on the water and energy nexus, presented cases from Sweden and Qatar where heat recovery has become a reality. The cases demonstrated how heat pumps are a game changer for thermal energy storage. The Qatar case highlighted the possibilities of resource circularity, where treated sewage effluent, in combination with chillers, was used to create a cooling network.

Danfoss was up next and presented the example of a hospital. Critical infrastructures like hospitals can benefit from a waste heat system as these types of infrastructure have heating and cooling needs. Installing waste heat systems increases overall energy savings.

The Danfoss case also discussed the potential of selling the excess heat to the district heating network, offering revenue opportunities for the hospital. Supermarkets are another example of cases that can greatly benefit from waste heat and cooling systems. Heat recovery in the case presented saved up to 90% on heating costs. Waste heat is used on-site and then sold to the district heating network, creating revenue for the supermarket.

Andrea Voigt, speaking on behalf of Danfoss, emphasised that more awareness needs to be created about the opportunities of waste heat -one of the goals of RE-WITCH, our Horizon-funded project demonstrating advanced thermally-driven industrial cooling technologies based on ADsorption and ABsorption processes, with a lot of resources and efforts focused on communicating project results and topics. Waste heat remains untapped, but it is a commercially viable solution as the above cases demonstrate. Andrea also highlighted that opportunities are already there to be exploited. For instance, across the Fit for 55 package, opportunities exist to make the most of waste heat:

  • Waste heat can be counted towards renewable energy targets under the Renewable Energy Directive.
  • Potential for efficiency in heating and cooling under the EED.

We need to create more awareness about these opportunities!

In addition, when combined with heat pumps, waste heat can be used to decarbonize data centres.

There needs to be an integrated approach, specifically for industrial sites to achieve decarbonization. Danfoss recommends taking a replicable 3-step approach.

1.       Reduce energy waste.

2.       Reuse energy – waste heat.

3.       Resource from green sources of energy.

Trane Technologies presented their results from a waste recovery case in a dairy farm. How to combine heating and cooling systems and break down the silos that exist? The farm had simultaneous cooling and heating demands and the challenge was to reduce both the carbon footprint and water consumption. The solution? Install air-sourced chillers with integrated heat recovery plus a heat pump. This allowed the dairy farm to save energy and reduce C02 emissions. An insight from this case is that the tech can allow for a fully electric system, but we need to make the business case for this and raise awareness.

One of the RE-WITCH demonstration cases is a food cooperative in Spain, where an absorption cooling plant will be installed (after testing and characterizing the performance of the hybrid absorption-compression technology.


The message is clear– waste heat can contribute to our decarbonization targets and commitments under the Energy Efficiency Directive (EED). Also, under the Energy Performance of Buildings Directive (EPBD), waste heat can have a key role as we transform new buildings to net zero. The possibility of recovering waste heat from buildings is a key area to be further explored.

Potential ways to incentivize the recovery of waste heat:

  • Obligation on producers of waste heat.
  • Incorporate into municipal heating and cooling plans and comprehensive assessments.
  • Risk mitigation framework and financing schemes.
  • Sectoral targets for recovery.

Rewarding and supporting the recovery of waste heat and educating the market is crucial. We need carrots not just sticks, incentives such as subsidies or tax breaks for companies who recover waste heat.

Another option could be to include waste heat in the savings counted towards white certificates.

There should also be a focus on waste recovery on site even if there is no district energy network. For onsite waste heat recovery, the tech is there and ready to be used. Awareness is the biggest hurdle to overcome to make the most of the potential of waste heat on-site. It is important to think differently about the current operation of heating and cooling systems, combining these two systems can increase efficiency.

Smaller solutions like microgrids should also be considered viable (for example, a few industrial sites connected to each other). For these types of solutions, there could be some improvement of the regulatory framework extended to microgrids, which have untapped potential. We need awareness around these solutions, especially the business case about heat recovery. These solutions represent and provide value for business and this message needs to be communicated more effectively.

Finally, we need implementation and plans brought to life. We need to accelerate the deployment of waste heat, as well as renewable sources.

Don’t forget water!

The energy sector needs to be less water-intensive, and wastewater needs to be treated as a resource. For example, there is a lot of potential for waste heat recovery in wastewater treatment plants. Heat pumps can transform waste like sewage into valuable energy, these synergies should be explored.

Policy proposals suggested during the session to enable waste recovery:

  • Broaden and refine the definition of waste heat.
  • Sectoral targets – a good way to measure the opportunities.
  • Make heat recovery onsite mandatory for new buildings.
  • Financial aspects to consider – the difference between gas and electricity prices should be addressed.
  • Channel rebates and subsidies into waste heat.
  • The EE1st principle should be applied across sectors.
  • Awareness is essential.

During the final moments, Pauline Lucas summarized the main takeaways from the session, these were:

  • Make concrete plans and carry them out.
  • Address lack of capacity.
  • Raise awareness- collaboration between industries, national and EU level policymakers, and cities.
  • Deploy the tech available- heat pumps and DH infrastructure.
  • Incentives are needed for industries.

An interesting and insightful session, it was great to hear about the innovative solutions that were already being worked on to make waste heat a valuable resource, one that can be used to fuel a green future for everybody.

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Event recording and more insights from the organisers.

Photo by rorozoa on Freepik.

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