Heat transition
The city of Aachen's carbon dioxide (CO2) balance from 2021 shows the heating sector as by far the largest source of CO2 emissions with a share of 42%, followed by the transport sector with a low 30% due to the pandemic (compared to 2019: 33%). At 28%, the lowest share is attributable to emissions from the provision of electricity. One of the major challenges for the city of Aachen is therefore the heating transition. The city has aligned its climate protection goal with the Paris resolution to prevent global warming and wants to do its part to preserve human life on Earth.
Heat transition cornerstone
With the support of STAWAG, RWTH, FH, Fraunhofer IEG and IHK, the tasks that are already foreseeable today for the conversion of the energy and heat supply were compiled.
To achieve a climate-neutral heat supply, the district heating network and the gas network as the central infrastructure must be converted from fossil fuels to renewable energies. The gas supply currently dominates with 39 percent of the city's heating requirements. With a share of five percent, district heating accounts for a significantly lower proportion of the heat supply. As part of the switch to renewable energies, the supply strategy also needs to be adapted: which infrastructure needs to be expanded where and in what form, and which may need to be scaled back?
STAWAG is already working on solutions. The last unit of the Weisweiler lignite-fired power plant will be taken off the grid in spring 2029. Up to now, 90 percent of the district heating for the city of Aachen has been extracted from this power plant. Local replacement solutions such as the extraction of heat from the neighboring Weisweiler waste incineration plant or the use of deep geothermal energy are already being investigated as future options. Outside of the district heating network, it is necessary to investigate whether other heat sources are available in the local area, from thermal to solar heat, and whether they can be used in a limited area.
Homeowners whose heating will soon need to be replaced and who want to be motivated to opt for climate-friendly building technology need information as early as possible about the infrastructure that will be available to them in the future. Will their house be located in the area of the district heating network or a local heating network in a few years' time or will an individual solution have to be found? In order to give private and commercial owners planning security, a city-wide heating plan should be drawn up as quickly as possible.
The energy and heating transition can only be achieved if all areas of society participate. That is why the administration wants to involve as many different areas of the city's society as possible in a broad-based communication process. As a first step, STAWAG, RWTH, FH, Fraunhofer IEG and IHK, which worked on the cornerstones of the heating transition, have signed a letter of intent (LOI) to support the city of Aachen in the development and implementation of the heating transition. On the one hand, the institutions themselves are all heat consumers; on the other hand, the research and university sectors in particular have the technical expertise for all issues that need to be solved on Aachen's path to climate neutrality. The IHK has an important function as a network of central target groups in the commercial sector.
The "Wärmewende Aachen" is intended to create a nationwide pioneering role for a climate-neutral city and a spirit of optimism throughout the city. The "Letter of Intent" (LOI) serves as a prelude to mobilizing further allies.
Municipal heat planning
The adoption of the Heat Planning Act (WPG) on 17.11.2023 obliges all cities with over 100,000 inhabitants to carry out and implement municipal heat planning by mid-2026. This therefore also applies to Aachen!
AI-X Heat
As part of AI-X Heat, they are preparing a strategy for the future synchronization of projects. Many digital tools, some of which already exist and some of which still need to be developed, are to be made usable for the overarching goal of digitized heat planning.