The generation of renewable energy (RE) is an increasingly relevant topic in many countries for a multitude of reasons, and the challenges related to its integration into existing energy systems are becoming more and more evident.
In Europe, heating demand makes up about one third of the total final energy demand, equivalent to the share for electricity. However, heating has received much less focus when it comes to the development of RE solutions than electricity. Particularly for cities, there are unresolved questions about how the heating demand can be covered in a feasible way in the future.
In Denmark, the introduction of RE has been ongoing for several decades, and district heating (DH) systems have been contributing to the flexibility of the country’s electricity production via combined heat and power (CHP) and thermal storage. However, this beneficial synergy is now declining because CHP production is being replaced with wind power. The 4 th generation of DH (4DH) is a concept that describes how DH and cooling should develop in the future to be able to adapt to changing conditions in the transition towards 100% RE systems.
The purpose of 4DH is to identify future challenges and solutions for reaching a 100% RE system. The concept includes the integration of the heating sector into the overall energy system and is seen as an integral part of smart energy systems. Smart energy systems is an analytical approach, which is applied in the analyses of this thesis.
The purpose of this thesis is to contribute to the solution of how DH should be developed in the transition towards a 100% RE system to meet societal goals of low socioeconomic costs and a sustainable use of resources. This is done through analyses of different issues related to the future of DH. The thesis is structured around three main areas:
1) New heat sources,
2) Reductions in heat demands
3) Changes in the supply system