Efficient district heating

The heat supply and thus also district heating in Germany must be climate-neutral by 2045 at the latest in order to achieve the climate targets to which Germany has committed itself by ratifying the Paris Climate Agreement. Fraunhofer IFAM is therefore working on the project “Definition and potential of efficiency in district heating networks (WäNEff)” to examine the future viability of efficiency criteria for district heating. The existing criteria and the integration of them into the regulatory law and / or the funding framework is examined and recommendations for the development of them are derived.

Recording the status quo of district heating - deriving efficiency criteria

As it is predictable that a residual amount of climate-relevant emissions cannot be avoided in other sectors, the energy sector must become completely climate-neutral. The efficiency criteria for district heating are necessary in order to accompany the process of defossiliating the heat sector with sensible legislation and funding and to be able to monitor it using various criteria.

In the course of the WäNEff project, we first look at the status quo of district heating in Germany from various perspectives, including

• the technical components in the building supplied with district heating
• the heat network itself
• possible efficiency improvements in existing buildings
• barriers to the planning of new efficient district heating networks
• comparison of the various concepts used throughout Germany and their legal and commercial implementation

Current efficiency potentials are to be identified and the reason why they have not yet been exploited investigated. Based on the detailed inventory and barrier analysis, we derive efficiency criteria that take into account both a high proportion of renewable energies and low losses in the grid and heat generation as well as in the upstream process chains. As it is already known in advance that some of these requirements counteract each other, more than one criterion will most likely be necessary.

We expect opposing effects, for example: the integrating of a heat storage can increase the proportion of renewable energy, but will always results in additional heat losses, so that the energy efficiency of the system decreases. Furthermore, the derived criteria should not hinder the expansion of district heating, as relevant studies on climate neutrality in Germany envisage an expansion of district heating, particularly in densely populated urban areas.

Project team has extensive experience in the heating sector

As the above examples show, the project demands  a high level of detail and therefore experience and competence of the project team. Fraunhofer IFAM acquired the project together with the Öko-Institut and GERTEC as their subcontractors. Within the consortium, Fraunhofer IFAM has many years of experience in municipal heat planning, the geo-referenced analysis of heat supply structures and energy management analyses.

Together with the Öko-Institut, Fraunhofer IFAM has already provided expertise on current energy-related issues to ministries and authorities on several occasions. The Öko-Institut also has experience in the analysis of process chains and resource efficiency and has also carried out numerous projects in the heating sector.

The third partner is GERTEC, an engineering firm with many years of experience in the planning and implementation of heating networks as well as in building technology and equipment.

Together, the three project partners cover expertise at all levels of district heating to be considered and can contribute project experience from both consulting and technical implementation.

Details on the “WäNEff” project

The project “Definition and potentials of efficiency in heating networks (WäNEff)” was put out to tender by the Federal Environment Agency on behalf of the Federal Ministry for Economic Affairs and Climate Action and is expected to run until August 2026.

Over the course of the project, several workshops will be held with relevant stakeholders (energy supply companies, associations, the housing industry, engineering firms, scientists), some of which will also be attended by representatives of politics and the press.