by Linda Bertelsen
Sector coupling

In times of fundamental transitions, like the transition of the energy sector, it becomes imperative to facilitate effective knowledge sharing to boost the general understanding of the sector and raise public awareness.

By Jan Eric Thorsen and Oddgeir Gudmundsson, Directors, Climate Solutions, Danfoss A/S

Published in Hot Cool, edition no. 7/2023 | ISSN 0904 9681 |


Energy system experts actively share information in the format of white papers and research papers and participate in various communication forums and conferences. While these activities are well suited to address specific audience groups, there is also a need to provide easy-to-grasp material, with as low entry barriers as possible, to communicate the benefits and importance of our sector to the politicians and the general public. In this aspect, we recognize that written documents can be considered a significant barrier in today’s fast-paced world, and a more relaxed and visualized approach may be better suited. With that perspective in mind, we started exploring the possibility of conveying our thoughts and insights on complex matters in a simple video-based format of shorter duration. As a first step in this journey, we have created a video series focusing on one of the trending topics in our sector: energy system integration via sector coupling.

Eloi Piel Eloi Piel, Head of Policy & European Affairs, Euroheat & Power:We must move beyond the rhetoric that the heat sector is complex and local. There is obviously complexity with the many actors involved and the diversity of potential solutions. And it is local, as operators valorize local streams of renewable and waste heat. This being said the contribution of sustainable and competitive district heat to the broader transformation of the energy system must be further explained to citizens and policy-makers on the basis of expert knowledge.”

Sector coupling – generating and sharing knowledge is key.

The terms smart energy systems, sector coupling, or sector integration are widely applied to scope the future green energy system. How it is perceived is often linked to the area of focus for the individual, where the terms are not always anchored in the bigger perspective, risking good intentions falling short of the true potential of the considered system.

This calls for networking and cooperation of experts across sectors and professions to generate helpful insights for developing a shared vision and understanding of the overall energy system. It is about painting the big picture with adequate details for revealing the “why” and “how.”

Over the years, we have had the privilege and pleasure of being part of such cooperations through numerous research projects and platforms, where the future energy system has been discussed, analyzed, and demonstrated. This has provided great insights and understanding we would like to convey further.

Brian Vad MathiesenBrian Vad Mathiesen, Professor Aalborg University:The first principle of energy efficiency is pivotal for handling the energy and climate crises. Through our research in Smart Energy Systems, e.g., in Heat Roadmap Europe, we can see that energy system design and the connection between sectors creates additional synergies and efficiency to the end demand savings. Based on our research, the heating sector plays a major role in the green transition, and sharing and explaining the message is key.”

Due to the complexity of modern energy systems, it is beneficial to approach the topic with different zoom levels, starting with a helicopter view to establish a shared vision and subsequently go into details of the building blocks of the energy system. This is particularly important when it comes to the introduction of fluctuating renewables and increasingly diversified energy sources.

Anders DyrelundAnders Dyrelund, District Energy Planning & Infrastructure Ramboll:The Danish energy planning based on economic assessment for the consumers and the society, including environmental impact costs of CO2, has paved the way for many important sector couplings. Most important is the coupling between buildings and district energy, as cities are growing, and district energy provides numerous sector couplings for cost-effective, resilient, low-carbon energy supply in cities. In particular, the couplings between district energy and electricity. If power-only generation is on the margin, district heating can utilize the surplus heat, thus cutting down fuel consumption for heating to less than 40% for society. In case of hydro, wind, or solar PV is on the margin and curtailed, district energy can utilize the surplus electricity which else would be wasted and even more offer balancing services to the grid. It is a cost-effective and simple “virtual battery.” Finally, district heating opens for environmentally friendly utilization of waste and surplus biofuels and further on for carbon capture and utilization.

Due to the complexities and number of actors involved in the energy system, initiatives like ProjectZero in Sønderborg can play a central role in boosting the knowledge level in their local communities and support the citizens and local companies to identify and implement energy-saving improvements, as well as energy saving behaviors.

Anne BrenderupAnne Brenderup, Senior Project Manager Project Zero:In Sønderborg, we have launched the ProjectZero mission back in 2007, with the aim to be CO2 neutral by 2029. Today, we are more than halfway on our journey. We cannot save the world, but we can show others that the solutions to keep global warming at a tolerable level for future generations are already here.

In Sønderborg, we have great companies, research, and educational institutions with energy efficiency and green technology knowledge. Right from the start, ProjectZero is built on strong local commitment and collaboration, and this unique community is the foundation for our success in creating a sustainable Sønderborg area in development and growth.”

Sector coupling videocasts

Based on the knowledge gained from long-term cooperation with experts in the energy sector, we have made a series of videocasts focusing on sector coupling, intending to share the insights and knowledge obtained over the years. The first videocast intends to provide a general overview of why sector coupling is important and its key elements. This overview provides the general framework for the subsequent videocasts, which focuses on successful examples of district heating systems benefitting from the principles of sector coupling.

Basic of sector coupling and the role district energy systems play

Copenhagen district heating

Copenhagen has a long and successful history of district heating, with the first scheme dating back to 1903. Over the years, more and more systems were built in Copenhagen and eventually interconnected to utilize a wide range of energy sources effectively. Today, 98% of all buildings, approximately 500,000 households, in Copenhagen are heated by the district heating system. The system is an excellent example of how large district heating systems can support and benefit from sector coupling. In the Copenhagen videocast, we present the main aspects of the system and explain how the district heating system is the key to ensuring a clean, affordable, and resilient heat supply to the city.

Lars GullevLars Gullev, Senior Consultant VEKS:Establishing the Greater Copenhagen district heating system has been possible due to a clear political objective from 20 municipalities in the 1980s, intending to utilize excess heat from fossil-based CHP plants and waste incineration. Today and in the future, the aim is to base the heat production on sustainable biomass, heat from waste energy plants, geothermal energy, large seawater-based heat pumps, surplus heat from Carbon Capture and PtX, data centers, and industry. The Copenhagen system is green and flexible; therefore, we are prepared for the future. And the future is not far away.”

How the Copenhagen District Heating System supports and benefits from sector coupling

Sønderborg district heating

In contrast to the Copenhagen video, the Sønderborg videocast aims to show how a small city, with 12,500 households, can successfully apply the same sector coupling principles to ensure affordable and decarbonized heat supply to its citizens. The Sønderborg District heating company supports this effort and, for example, introduced geothermal energy supplemented with sustainable biomass and electrical boilers. Now, the quest continues with extending the district heating infrastructure to other towns in the municipality and taking advantage of waste heat sources and local renewables in the area to increase the energy supply security and strengthen the local economy. In the Sønderborg videocast, we introduce the system design and the many sector coupling opportunities commonly available in smaller communities.

Tue ChristensenTue Gejl Christensen, Project and Development Director, Sønderborg Utility: “District heating can do much more than heating the buildings. It’s an integral part of lowering the energy footprint by utilizing waste heat, e.g., from industry, and stabilizing the electrical grid with the capability to harvest heat and store it when there is ample energy production from solar and wind.”


How the Sonderborg District Heating System supports and benefits from sector coupling

The three videocasts show that while the green transition is a challenging journey, it is possible, and the necessary building blocks and solutions are already available. A critical starting point is to establish a basic understanding of sector coupling and the role of the different sectors, particularly the interconnecting ability of the district energy system. Due to the high complexity level, it can be challenging to visualize, and that is why showcasing successful examples of sector-coupled and smart energy systems is key to build up general knowledge and inspiring cities on their journey toward sustainability.

The future aspiration

The sector coupling videocasts is the first series to share knowledge and insights. The series provides a holistic overview of the energy system and the role of district energy in particular. It provides the foundation for future knowledge sharing, focusing on the underlying aspects and technologies applied. In that respect, new ideas are lined up for additional series, and we look forward to sharing them with you.

Charlotte KjærCharlotte Kjar, Marketing Communications Manager Danfoss:At Danfoss, we support and drive the green agenda on decarbonizing heating and cooling. We aim to engage our audience on technologies and know-how enabling the green transition. As the video format is easily accessible and more memorable than, e.g., written reports, we are using the format to a larger extent in relation to high-level thought leader topics. This gets the message across as a short, yet concise narrative will engage with our audience in a way that text can’t achieve.”

For further information please contact: Jan Eric Thorsen, jet@Danfoss.com

Meet the authors

Jan Eric Thorsen
Climate Solutions, Danfoss A/S
Oddgeir Gudmundsson
Climate Solutions, Danfoss A/S
“The importance of knowledge sharing” was published in Hot Cool, edition no. 7/2023. You can download the article here:
The importance of knowledge sharing, Hot Cool article by Jan Eric Thorsen and Oddgeir Gudmundsson_