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in the 73rd issue of our heatbeat Research Newsletter, we look at how thermal energy storage and the exchange of heat between industry and district heating can ease the electrification of industrial process heat. This is an exciting example of the future role of district heating in the energy system. News reports on district heating from October also show that this role is becoming increasingly challenging.
A new VKU survey finds that 54% of municipal utilities in Germany expect district heating prices to rise next year. A key factor behind this is that the TTF gas price has now risen to over 100 EUR/MWh through the end of October. On the other hand, recent court rulings are causing uncertainty regarding the validity of price escalation clauses. The legal clarity regarding price adjustments—which is urgently needed for major investments—was therefore appropriately included in the key points paper published last month by the Conference of Energy Ministers. In addition, financing options for district heating network expansion and a consolidation of existing regulations are on the horizon. However, it will still take some time before a District Heating Network Act can be passed. Progress is expected to move somewhat faster with the amendment to the KWKG , which is scheduled for the first quarter of 2027. Meanwhile, the backlog of BEW applications has nearly doubled compared to last year , reaching almost 2,000 applications. We hope that important district heating network projects can continue to move forward despite the challenging environment.
Meanwhile, we were able to make some significant progress again in October with the heatbeat Digital Twin. A highlight for us was the launch of infra fürth’s new website. An interactive map for the district heating expansion is now available there at https://www.infra-fuerth.de/energie-wasser/waerme/fernwaerme . This map is generated directly from the heatbeat Digital Twin and integrated from there into the infra fürth website. We would like to thank infra fürth for their close and trusting collaboration, which now also enables us to communicate the expansion plans from our Digital Twin directly to the public.
Another key focus of our development efforts in October was improving the performance of the map view for large datasets, such as municipalities with tens of thousands of buildings and district heating networks with many customers. Through a fundamental overhaul of the map view, we were able to significantly improve the fluidity of work within the Digital Twin and lay the groundwork for further enhancements. One of these enhancements is the new Photos & Notes feature. This feature allows all users to add comments directly in the map view, as well as upload photos or PDF files and geotag them to the map view. For example, this feature is already being used to document photos from network condition assessments or plans of manholes and specific network sections right where they are most useful to heating network operators.
In addition, there have been numerous minor improvements: We’ve added more fields to the building dashboard so that the basis for calculations can be documented even more comprehensively—for example, with the number of residential units, the percentage of heated floor area, or the number of residents. For connection capacity, we now display both the capacity at the pipe level and the available connection capacity based on the feed-in even more clearly, making it easier to identify bottlenecks and understand capacity levels. In addition, our revamped download section now always offers the option to export the heating network as a technical drawing in DXF format. And on top of all that, as we do every month, we’ve incorporated additional security and performance updates to ensure that the heatbeat Digital Twin operates as securely and stably as possible.
Electrifying industrial process heat ties industrial decarbonization to the limits of the power system. The open-access study in Energy asks how thermal energy storage (TES) and heat exchange between industry and district heating change the cost-optimal decarbonization pathway of a synthetic, representative region in Germany at district level (NUTS 3, the EU’s statistical classification for regions of roughly district size; here a city and its surroundings as typically supplied by one district heating network).
The authors use a linear cost-optimization model (EnergyModelsX, solved with Gurobi) with perfect foresight. It covers five investment periods of five years each (2025 to 2050), every period represented by one year at hourly resolution. An annual CO₂ cap tightens to 100, 70, 47, 24 and 5 % of the reference level and is binding from 2035. Three industry sectors (pulp, paper and tobacco; food and beverages; machinery) are modeled at four temperature levels (excess heat about 40 °C, low temperature 80 °C, medium 150 °C, high above 200 °C). District heating is supplied by gas and coal combined heat and power plants (CHP; coal until 2035), a renewable heat node, large heat pumps (constant COP of 3), electric boilers and a generic dispatchable carbon-free option as costly peaking capacity. Industrial heat pumps reach COPs of 4.8 (excess heat to 80 °C) and 2.7 (80 °C to 150 °C). The model also represents the power system (build-out of wind, solar and batteries, curtailment; existing supply priced with the 2024 German day-ahead profile; discount rate 4 %), so “system costs” refer to the whole energy system, not to the books of a single network operator. TES is available as pit and tank storage in district heating and at three temperature levels in industry. Four cases combine TES (yes/no) with an industry–district heating connection (yes/no).
With TES, total system costs fall by 6 to 12 %, wind and solar curtailment is reduced, and up to 36 % of the cost-optimal battery capacity is replaced. Most of the savings consist of investment costs: less heat pump and peaking capacity is needed in district heating, because TES moves heat pump operation away from peak hours and the installed capacity is used more evenly. In industry, low-temperature TES pays off early and smooths heat pump operation; high-temperature TES only becomes relevant in late, highly electrified periods, when it shifts power-intensive heat production in time under grid constraints.
Allowing heat exchange reduces the need for low-temperature storage in industry and district heating alike. In the first periods, industry is a net exporter: existing industrial gas boilers cover district heating peaks, so district heating heat pumps can be sized for base load. From 2035 on, the flow reverses. Industry draws 80 °C district heat as the source for high-temperature heat pumps, which then replace electric boilers for medium-temperature demand (150 °C). Exchange is limited to 100 MW per sector (a quarter of the initial district heating peak) and this limit is reached in all cases. Coupling alone lowers discounted system costs by 7 % (about 780 million EUR across the three sectors). Once TES is in place, coupling adds only a further 1.6 percentage points (about 55 million EUR per sector). According to the authors, TES yields the larger cost reduction, and combining both adds only a marginal further benefit.
In our reading, the value of storage lies less in shifting energy than in avoided capacity, i.e. smaller peaking units and heat pumps sized closer to base load. The authors compare the benefit with Danish cost figures (about 2.7 million EUR per km of pipe pair, 14 million EUR for a 100 MW heat exchanger station): the stand-alone benefit would pay for roughly 90 km of connection, the more conservative benefit alongside TES for roughly 15 km, and the latter becomes marginal beyond about 10 km or if a pump station is needed. These figures exclude land acquisition and network reinforcement. Most of the benefit arises on the district heating side, so a single industrial investor would capture only part of it; tariffs, supply contracts and responsibility for security of supply (for example where industrial gas boilers cover peaks) matter as much as technology. For transferability, temperatures are decisive: the study assumes fixed supply temperatures and constant COPs, whereas real networks with higher or varying flow temperatures and temperature-dependent COPs can shift the results in either direction, and heat extraction by industrial heat pumps must be compatible with return temperature requirements.
The model is a planning model, not an operations study: perfect foresight overstates the benefit of the connection, the 100 MW exchange limit is binding in all cases, heat pump COPs and supply temperatures are fixed, and there is no network hydraulics or variable temperature level. The assumed excess heat shares (20 and 30 % of demand) are, according to the authors, optimistic compared with about 10 % in the literature. Pit storage reaches its assumed capacity limit in all runs, and cost data come from Danish sources. The results show orders of magnitude and mechanisms for a synthetic region, not values for a specific network.
As always, we recommend reading the full article. Case setup, input data and scripts are openly available, which makes the study well suited for checking your own assumptions on storage, heat pump sizing and industrial heat sources. If you would like to discuss how such effects can be evaluated for your network, please get in touch.
The next issue of our newsletter will be published on December 2, 2026. Until then, we are especially looking forward to HeatExpo, taking place November 24–26 in Dortmund. You’ll find us at Booth 4.E72.
This article was created with the support of AI.