In the journey towards a sustainable future, district heating networks are discovering a powerful new ally: surplus heat from Power-to-X and Carbon Capture processes. This dynamic duo has the potential to play a pivotal role in the way we think about energy efficiency and decarbonization in heating our homes and industries.
By Jannick Hauschildt Buhl, Head of CCUS and PtX at the Danish District Heating Association
Published in Hot Cool, edition no. 3/2024 | ISSN 0904 9681 |
Power-to-X technologies have emerged as a game-changer in the renewable energy landscape. These processes, e.g., electrolysis and methanation, convert renewable electricity into valuable resources such as hydrogen, synthetic methane, e-methanol, and Sustainable Aviation Fuel (SAF). These products will be necessary to decarbonize heavy transportation and some hard-to-abate industry sectors where it is impossible to use electricity directly.
Similarly, while the world must first and foremost aim for rapid and deep emission reductions, it is by now clear that industrial Carbon Capture and so-called carbon removals, where CO2 is essentially removed from the atmosphere through, e.g., capture and geological storage of CO2 from biogenic point sources, will be necessary if the world shall have a reasonable chance of staying within the limits of the Paris Agreement, according to e.g. the Sixth Assessment Report from the Intergovernmental Panel on Climate Change (IPCC).
Harnessing the green potential
In the coming decades, Power-to-X and Carbon Capture technologies represent some of the primary climate-change mitigation technologies in the energy-, transport- and industrial sectors. However, as with many other industrial processes, they also produce significant amounts of surplus heat as the production processes are not 100% efficient.
In fact, up to 25% of the energy used for Power-to-X and Carbon Capture can be utilized in district heating, providing a significant opportunity for energy efficiency and resource optimization. Of course, the percentage of surplus heat will decrease over time with technological advancements. However, as the needed scale of Power-to-X and Carbon Capture facilities is very large, the long-term potential for sector integration remains even if the potential per MW installed capacity is reduced.
Almost 70% of all homes in Denmark are heated with district heating. At the same time, Denmark has enormous potential for developing Power-to-X through the expansive renewable power resources, especially from offshore wind. Hence, it is natural to consider integrating the surplus heat from the Power-to-X processes into the district heating grid to improve overall energy efficiency. According to a study by researchers at Aalborg University, surplus heat from Power-to-X can potentially provide about 10% of the Danish district heating consumption by 2045.
Creating value for all while reducing carbon emissions
The utilization of surplus heat from Power-to-X in district heating systems is beneficial not only for district heating companies. In fact, it creates value for all parties, including the Power-to-X companies and the district heating customers. By utilizing surplus heat, Power-to-X companies gain a secondary revenue stream, which not only makes these sustainable fuels more competitive in the market but also accelerates the transition towards a greener energy landscape.
At the same time, by tapping into surplus heat, district heating systems can provide CO2-neutral heating, offering a viable alternative to fossil fuel-based heating. Hence, it not only enhances the overall energy efficiency of Power-to-X processes but can also reduce costs for consumers and the overall carbon footprint of district heating. This partnership between Power-to-X producers and district heating providers is a win-win, ensuring a more sustainable and cost-effective energy solution for both parties.
Real-world examples from Denmark
Let’s take a closer look at how Danish district heating systems and Power-to-X companies are working together and leading the charge towards this green revolution. In Copenhagen, the district heating companies VEKS and CTR are working in collaboration with Ørsted , a leading renewable energy company, to utilize the surplus heat from Ørsted’s coming Carbon Capture plant, which will be installed at the straw-fired boiler at Avedøre CHP plant in Copenhagen. This innovative partnership, which will be able to heat 16,000 homes, is beneficial to all parties involved and a good showcase for sector integration.
Everfuel owns and operates the hydrogen production product HySynergy. Located in Fredericia, HySynergy produces green hydrogen through electrolysis, with excess heat from the process utilized in the district heating system. The video was created by Arkikon.
Similarly, the district heating company TVIS has embraced the potential of surplus heat, working closely with the hydrogen production project HySynergy, owned and operated by Everfuel. Located in Fredericia, HySynergy produces green hydrogen through electrolysis, with excess heat from the process utilized in the district heating system.
In the first phase of the project, which includes 20 MW electrolysis, the excess heat can heat up to 1,800 homes every year. The second and third phases of the project aim to install 300 MW and 1 GW electrolysis, respectively, thereby increasing the potential for district heat integration significantly.
Copenhagen Infrastructure Partners (CIP) is working on its 1 GW HØST PtX project in Esbjerg, on the west coast of Denmark. The project aims to produce both hydrogen and ammonia. The excess heat can heat up to 15,000 homes in the district heating network of Esbjerg, owned and operated by DIN Forsyning.
The above examples are all good showcases for using excess heat from Power-to-X and Carbon Capture in district heating. In general, it is essential to consider the location of Power-to-X facilities to ensure that the surplus heat can be utilized as much as possible in district heating systems.
Figure 1: Up to 25% of the energy for Power-to-X and Carbon Capture can be utilized in district heating. Sources: The report ”Power-to-X and District Heating” by the Danish District Heating Association, Grøn Energi, COWI and TVIS estimates a potential for utilizing surplus heat from electrolysis of up to 25%, while the report ”CO2 capture at Danish waste-to-energy plants” by Rambøll for Dansk Affaldsforening estimates, that carbon capture can increase the heat production from the CHP or Waste-to-Energy facility by up to 20% compared to a plant without carbon capture.
Strategic placement of these facilities can maximize the efficiency and benefits of this integration, creating a win-win situation for all stakeholders involved. Therefore, Power-to-X companies should look at the complete set of infrastructure needs when finding the best location, including the possibility of selling surplus heat to district heating.
The integration of surplus heat from Power-to-X in district heating systems not only benefits Danish cities but also has a broader global impact. By showcasing successful examples of this integration, Denmark can serve as a model for other countries looking to transition towards sustainable energy systems. This accelerates the global fight against climate change and opens up new avenues for technological innovation and international collaboration.
For further information, please contact: Jannick Hauschildt Buhl, jhb@danskfjernvarme.dk
“Utilization of surplus heat from Power-to-X and Carbon Capture in district heating is a win-win” was published in Hot Cool, edition no. 3/2024. You can download the article here:
