First the electric car, now the heat pump. Some technologies have been on the market for a long time, but only come out of their niche when politicians support them and public opinion turns. The heat pump, which uses electricity to use the temperature differences in the environment, is currently on everyone's lips because of the Building Energy Act. This major project by Economics Minister Robert Habeck (Greens) envisages that from 2024 onwards, only new heating systems will be installed that run at least 65 percent on renewable energies.
Christian Geinitz
Business correspondent in Berlin
- Follow I follow
The heat pump powered by green electricity is Habeck's preferred solution and is also convincing more and more consumers. No other heat generation is growing faster than that with combined heat and power engines: 2022,236 units were installed in 000, 53 percent more than in 2021. In the first quarter of 2023, sales more than doubled year-on-year to 96,500 units. According to the German Heating Association (BDH), one in three new heating systems is now a heat pump – without any obligation to replace them.
In front of the house and in the garden
However, there are many applications where the devices, which are usually set up in front of the house or in the garden, are only partially operational. This applies in narrow or uninsulated buildings or generally where very high flow temperatures are required, especially for industrial process heat.
So are these fields unsuitable for heat pumps? No, says a study by the Berlin-based think tank and lobby organization Agora Energiewende entitled "Rollout of large-scale heat pumps". According to their findings, Germany can cover its entire heat demand for temperatures of up to 200 degrees without carbon dioxide. And this is done with large-scale heat pumps, which use geothermal energy as well as environmental and waste heat. These sources are available in sufficient quantities for both district heating and industry, according to the study, which is available to the F.A.Z.
Even without using the ambient air, the potential heat output from CO2-free sources is said to be 1500 terawatt hours per year. The heat requirement of up to 200 degrees Celsius is only slightly more than 1000 terawatt hours. Near-surface and deep geothermal energy, lake and river water, industrial waste heat, wastewater, coal mines and data centers could be used.
Heating networks need temperatures of 90 to 110 degrees, while industrial production requires process heat of up to 200 degrees. Large-scale heat pumps can already do both, but they still only have an installed line of 60 megawatts; one terawatt is one million megawatts. But the potential is enormous, if you can believe the Fraunhofer IEG Institute, which prepared the study for Agora. The prospects are particularly rosy for district heating, on which ever greater hopes rest since it became clear that small heat pumps would be difficult to install in the dense urban, often unrenovated existing buildings. By 2045, if Germany wants to be greenhouse gas neutral, large-scale heat pumps could provide more than 70 percent of district heating and thus largely replace natural gas, Agora writes. Then more than a quarter of all apartments could be heated with "green district heating", says Simon Müller, the German director of the Agora.
Germany as a leading producer?
To do this, however, 4000 megawatts would have to be added annually. In order for this to succeed, the organization is calling for a clear expansion path with binding municipal heat planning, with the reduction of price disadvantages compared to fossil fuels and with a strategic expansion of the supply. This could be achieved through industrial product standardization; so far, expensive one-off productions predominate. Germany would then have what it takes to "position itself as a leading producer of large-scale heat pumps". Müller sees the disadvantage of eco-heat pumps in the fact that fossil plants of combined heat and power generation as well as heat pumps powered by fossil waste heat receive more subsidies.
Norway and Sweden showed how the ramp-up of green technology can succeed. Here, the share of these large-scale heat pumps in district heating is already 13 and 8 percent. Finland, Denmark and a large country such as France also managed more than the EU average of 1.2 percent. For Germany, on the other hand, the study shows 0 percent. Müller called for a reform of the law on combined heat and power generation and an increase in the subsidy programme for heating networks. Large-scale heat pumps are indispensable for decarbonisation, as heat generation of up to 200 degrees for buildings and industry accounts for three-quarters of Germany's energy consumption and is responsible for more than a quarter of greenhouse gas emissions.