Big things: The pipes that distribute the hot water into the district heating network. © Marijan Murat/DPA
Heating in Germany is to become more climate-friendly. In addition to the use of heat pumps, the traffic light coalition in Berlin is primarily aimed at expanding district heating networks. Murnau has been relying on it for years. How good is the supply in the market and what could it look like in the future? An inventory.
Murnau – The goals set by the traffic light government are ambitious – especially in the areas of climate, energy and heat. One means of implementing this is the expansion of district heating. Six million of the 43 million apartments in Germany are currently heated with it, and it is said that this could lead to 18 to 20 million in the future. District heating is particularly suitable for apartment buildings in cities and densely populated areas. With its approximately 12,000 inhabitants, Murnau is one of the smaller medium-sized centres, and yet the market has been able to afford a district heating network for years, which is supplied via the plant on the Kemmel site and is relatively well received. "We currently have about 100 connections," says Karl Steingruber, commercial director of the municipal utilities, and their number is likely to skyrocket in the future. "The demand is very high at the moment."
However, Steingruber makes it clear that he will have to reject certain interested parties, because the district heating supply cannot be extended to the entire municipal area. "An expansion of the district heating network for the whole of Murnau will neither be financially possible nor make sense in terms of energy technology," he clarifies. For areas for which district heating is not suitable, according to him, "a district concept should be drawn up".
For houses in peripheral locations, only a heat pump is likely to be the method of choice. In the case of large buildings and high heat demand, however, according to Steingruber, they "quickly reach their limits and also require a lot of electricity". Not even all properties owned by the market are suitable for connection. "If a long route is necessary, other options will also be examined here," says the plant manager.
Speaking of the concept. According to the draft law, which comes from the Federal Ministry of Economics and the Federal Ministry of Housing, states and municipalities are to present concrete plans in the coming years on how they want to convert their heating infrastructure to be climate-neutral. This is intended to give citizens an important orientation by finding out whether their house will soon be connected to a district or local heating network – or whether they should convert their heating to a heat pump in the foreseeable future. Municipalities like Murnau will have to conjure up such a paper from the drawer by the end of 2028. Can this succeed? The manpower to pore over numbers and create tables seems to be there. "Once the climate protection manager has been hired, this will become the main task of the new employee," Steingruber believes. "For public buildings, this should be possible within the specified timeframe." Software for the recording is already available in the real estate office.
As a municipal company, the municipal utilities should work as economically and profit-oriented as possible. This has not been entirely successful with district heating recently. At the meeting of the works committee in October 2022, Helmut Mair, the company's technical director, had to admit that the company was slightly in the red. "The connection density and heat consumption are crucial for the economic efficiency of a district heating network," explains Steingruber. That is why it is important that the connected buildings have a certain size or heat requirement. The consumer advice centre comes to an identical conclusion. "The relocation of the grids and the construction of the generation plants are usually associated with considerable costs." A calculation example: According to experts, a single-family house in Murnau costs between 800 and 1000 euros per meter of burial, while the meter in the building costs 100 euros. A chunk of money quickly comes together, which puts a heavy financial burden on the owner.
The planned Building Energy Act also includes specifications for heating networks. For example, there should be an obligation to use at least 2030 percent renewable heat or waste heat in existing heat by 50. For new heating networks, a share of 65 percent is to be required. The Murnau plant on the Kemmel site already meets these requirements. "Currently, we can generate about 68 percent of our heat demand with the biomass heating plant. The goal will be to increase the proportion and only use gas and oil burners during peak loads or emergency supplies," says Steingruber.
In addition to a number of advantages offered by district heating, the consumer advice centre also lists a serious disadvantage. There is a lack of competition: every district heating network is a local monopoly, and it is not possible to switch to another supplier. You bind yourself to a provider in the long term. Anyone who paid several thousand euros for a connection a few years ago will hardly put a heat pump in their garden.
"An expansion for the whole of Murnau will neither be financially possible nor make sense in terms of energy technology," says Karl Steingruber, head of the Murnau municipal utilities. © MM