In the Franconian city of Bamberg, an entire district is being developed – 100-year-old buildings next to new buildings. The special thing about this district in Bamberg is the heating concept, says Michael Fiedeldey, Managing Director of Stadtwerke Bamberg, and Federal Minister for Building, Klara Geywitz. The SPD politician recently visited the construction project.
"We're able to generate between 70 and 80 percent of the energy that this heterogeneous district needs here from renewable sources. That's exemplary," says Fiedeldey. In the new heating concept, he relies primarily on large heat pumps. For example, they use the heat from the Bamberg sewage network. In addition, large geothermal collectors are distributed throughout the site. These are tubes in the ground that collect the heat there for the heat pump.
The building minister is satisfied: "You have already implemented what will be the legal standard of the future." That future isn't that far away anymore. A new rule will apply from 2024. Each new heating system should then be operated with 65 percent renewables – as a contribution to the climate goals.
Which heaters are suitable?
If the old heating system breaks down, the heating system that is then installed must meet this condition. What does that mean specifically? "We in the Ministry of Building always say that openness to materials is important, openness to technology is important," says Geywitz: "But the heat pump is a key player in the field of heating transition."
The heat pump makes it easy to meet the new requirement because it can be 100 percent renewable. But in many old buildings, it is not so easy to replace gas or oil heating with a heat pump. The owners have to renovate – sometimes more, sometimes less expensive – or resort to alternatives.
The Ministry of Construction and Economics have developed an initial concept with proposals. For example, homeowners can be connected to district heating – if there is one on their street. If you have enough space, you can also install a heater with wood pellets or wood chips.
Hybrid heating could be the solution
If none of that is possible, only a very individual decision can help, says Norbert Azuma-Dicke from the Association of the German Heating Industry: "The challenge is that the buildings in Germany are all so different. It will be very difficult to make a specification which will have to be fulfilled by all buildings."
This means that every owner will have to calculate individually for his house how he comes up with the 65 percent. It could often come down to hybrid heating, i.e. gas heating combined with a heat pump or solar thermal system on the roof, for example. It would also be possible to heat the gas heating with renewable gas, such as green hydrogen or biomethane. But these gases are not yet available in large quantities, and they will probably be very expensive for years to come.
Specifications could cause trouble
So there is a lot to come for real estate owners. Fideldey from Stadtwerke Bamberg fears that the 65 percent requirement could lead to anger and a lack of understanding. He considers the current transformation process, which is supposed to take place in such a short time, to be extremely difficult: "In addition, there will be the discussion that it will trigger, for example about affordability. It will be infinitely difficult."
Many questions are still open. The construction and economics ministries are working on a draft law. Property owners will only know what to expect when it is finished.