Large heat pumps as sleeping giants

June 15, 2023

Source: Energy & Management Powernews

Wake-up call for the heat turnaround: Large-scale heat pumps could provide about 70 percent of district heating by 2045, Fraunhofer researchers say. They name three prerequisites.

That engineers speak about their research subject in metaphors is rather rare. Fabian Ahrendts of the Fraunhofer Institute for Energy Infrastructures and Geothermal Energy (IEG), however, sums up the results of a new study by the house this way. The "sleeping giant" is the large-scale heat pump among sustainable heating technologies, the head of the Competence Center for High-Temperature Heat Pumps fabulates. Together with a dozen colleagues, Ahrendts has presented a 140-page study. In it, they shed light on the current market status and development potential of large-scale heat pumps. The study is titled "Rollout of large heat pumps in Germany: strategies for market ramp-up in heat grids and industry."

Status quo: 60 megawatts of total capacity

The Fraunhofer researchers conclude that the entire heat demand up to 200 degrees in this country could be met "technically completely" by heat pumps. Large-scale heat pumps, they write, "can leverage significant potential in geothermal energy, water bodies and waste heat." By 2045, they say, it would be possible to secure 70 percent of the district heating supply on this basis. "With the next development push, the technology will reach temperatures of up to 200 degrees and thus the working temperature not only of existing district heating networks, but also of many processing and drying processes in the paper, food, chemicals and coatings industries," Ahrendts explains.

The IEG surveyed pump manufacturers for the study, which it says also gave it a picture of the status quo on the market. According to the study, at least 30 heat pump systems, each with a thermal output of more than 500 kW, were in operation in Germany at the beginning of this year. The study authors put the total output at around 60 MW. At least 30 further large-scale heat pump projects with a total output of around 600 MW were under construction or in planning at the time of the survey.

In total, the potential heat output that heat pumps can provide from CO₂-free sources even without using ambient air amounts to around 1,500 billion kWh, they say. This compares with an annual heat demand for temperatures up to 200 degrees totaling just over 1,000 billion kWh.

Fraunhofer experts urge "clear target picture"

In order to achieve the 70 percent share in district heating supply, the IEG believes that an average of 4,000 MW of large-scale heat pump capacity must be added annually. The Fraunhofer experts cite three prerequisites that need to be created:

- a clear expansion path based on binding municipal heat planning,
- the reduction of price disadvantages compared to fossil fuels,
- a strategic expansion of the heat pump offer, for example through the standardization of production processes.

Overriding is a clear target image required, combined with transformation-compliant energy prices, and reformed network charges, summarizes the IEG. The institution also sees a need for reform in the area of subsidies. The existing subsidy system via the Combined Heat and Power Act (Kraft-Wärme-Kopplungsgesetz) and the higher tax burden on electricity compared with natural gas have so far favored gas-based heating solutions. These misguided incentives need to be eliminated. In an international comparison, the IEG considers Germany to be at an early stage in terms of market development. The researchers point to Norway and Sweden, where large heat pumps account for 13 and 8 percent of district heating supply, respectively. Finland, Denmark and France are also already further ahead.

With this study, the IEG is supplementing its roadmaps on near-surface geothermal energy and deep geothermal energy. The study was commissioned by the organization Agora Energiewende.

Fraunhofer IEG makes the study "Rollout of large-scale heat pumps in Germany: strategies for market ramp-up in heat grids and industry" available for download on its website.

Author: Manfred Fischer