Decentralised heat supply in a climate-neutral Germany

Our assignment

The “Climate-neutral Germany 2045” scenario (KNDE2045) shows a possible path to achieving climate neutrality by 2045. The main results are a significantly higher power consumption (+70 percent) due to the increasing use of electricity, including for heating and transport, and a significantly higher peak generation (+300 percent), due to the significant expansion of renewable electricity generation.

In 2045, 14 million heat pumps in Germany will be part of the solution for the building sector. For the Climate Neutrality Foundation, our energy system simulation team classifies the role of the heat pump as opposed to hydrogen heating in decentralised heat generation based on the KNDE2045 scenario.

The analysis focuses on the following two aspects:  
 

1. Does a power system with a high proportion of renewable energies and a significantly higher electricity demand also require significantly higher dispatchable power plant capacitry?  
   
   This question could be answered with the already published scenario Climate Neutral Deutschland 2045 (KNDE2045): the required dispatchable power plant capacity increases by about 20 percent. Compared to today's excess capacity, the net result is even a decrease in the necessary controllable output. The increasing number of flexible consumers can integrate the RES supply with their storage capacities and delay the demand for electricity. In combination with imports, the increase in maximum residual load thus remains low.
    
2. Could the use of hydrogen heaters instead of heat pumps be suitable for reducing residual load and thus increasing the efficiency of the system as a whole?
   
   Hydrogen heating makes the path to climate neutrality more difficult to achieve, results show. Hydrogen heating makes the entire system more inefficient because hydrogen demand is significantly increased, and the integration of renewable energies is less efficient.

The study highlights the central role of heat pumps as part of these flexible consumers in a renewable electricity system. Heat pumps offer two main advantages: firstly, they generate the majority of their heating energy from environmental heat. Secondly, with the thermal storage mass from buildings and heating circuit buffer storage, they will offer flexibility in power demand. "This allows more renewable electricity to be used, and less electricity to be curtailed", explains Hans Dambeck, project manager of the study.

How we proceed

In the analysis, a sensitivity of scenario KNDE2045 was modelled, in which the number of electric heat pumps was reduced from 14 to 13 million and the electricity requirement is thus reduced by nine percent. The results of the hourly modelling in the Prognos electricity market model compared with the base scenario KNDE2045 were used to draw conclusions about the influence of the heat pumps.  

"The reduced power consumption only leads to a lesser extent to a reduction in electricity generation from controllable hydrogen power plants. The other part is due to a higher curtailment of the RES-electricity and a reduced import balance. The required guaranteed performance hardly drops, by only 0.2 GW”, describes Aurel Wünsch, analyst of the electricity market modelling.

The use of 1 million hydrogen heaters, on the other hand, leads to a hydrogen requirement around twice as high as the need to protect 1 million heat pumps with hydrogen power plants in the power system.

As a result, hydrogen is used much more efficiently for dispatchable powerplantsbalancing a renewable power system with heat pumps than in decentralised heating systems. Heat pumps can significantly increase flexibility for the integration of the RES-electricity and the use of environmental heat. For these reasons, they are a central building block for a climate-neutral Germany.

Links and Downloads

To the study (PDF, in German)

To the policy paper (PDF, in German)

More information (website Stiftung Klimaneutralität)

The “Climate-neutral Germany 2045” scenario

Project team

Hans Dambeck, Aurel Wünsch, Marco Wünsch, Miriam Lovis