Carbon capture

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.