On behalf of the Munich Public Utilities, the FfE investigated the current heat consumption structure of the residential building stock of Munich. The focus here was not on a detailed quantitative analysis, but on deriving basic measures and action recommendations to achieve the climate targets for the city of Munich by 2040. First, an emission balance was carried out for the current housing stock. In a second step, the buildings were grouped together (clusters) so that the same packages of measures could be applied to the buildings within a cluster. Four overarching measures were identified and eight measures were quantified for the five building clusters. In two scenarios - ambitious and forced - the potential reduction of CO2 emissions by 2040 was estimated. In addition, a target scenario with corresponding measures was calculated, which corresponds to the necessary savings for the climate protection target of Munich.
Figure 1: Measures considered in the three scenarios.
The results show that if the previous efforts are continued (ambitious scenario), the city's climate target will clearly be missed. Even with optimistic but still realisable assumptions (forced scenario), a gap remains. The target scenario cannot be achieved under current conditions.
In 2014, heat-related CO2 emissions from the Munich building stock amounted to 2.8 million tonnes. The division by building type and energy source is shown in Figure 2.
Figure 2: Total building heating - CO2 emissions by building type and energy source.
In September 2017, the City Council adopted the "Munich Climate Neutral Scenario" from the Öko-Institut's study "Climate Protection Goal and Strategy Munich 2050". This suggests that heat-related CO2 emissions (space heating and hot water from private households) must be reduced by around 70% between 2014 and 2040. Considerable savings are needed to achieve this goal.
First, overarching solutions were identified, which can be applied to all analysed building groups:
- Avoid unnecessary energy consumption - targeted restructuring
- Use of renewable energies - exploiting regional potential
- Optimize remaining consumption - smart solutions through digitisation
- A holistic approach to the Energy Transition - flexibility through sector coupling
80 of CO2 emissions are caused by residential buildings (single and multi-family houses). The following analyses therefore focused on this sector. In addition, CO2 reduction measures for new buildings, area concepts and commercial buildings were qualitatively investigated.
In order to derive specific solutions for individual building groups, the Munich residential building stock was divided into five groups according to heat energy source (district heating, heating oil and natural gas), building type (single and multi-family houses) and available infrastructure (district heating network available). Figure 3 gives an overview of the measures analysed for each building group.
Figure 3: Analysed measures per building group
[1:] These measures are only considered in the target scenario
[2:] In the ambitious and forced scenario, heat pumps are only investigated for use in single-family houses, in the target scenario also in multi-family houses outside the district heating area.
In order to calculate the possible CO2 savings by 2040, annual implementation rates had to be defined for the individual measures. Three scenarios were distinguished: The "ambitious scenario" assumes that the current implementation rates will be maintained until 2040. In this scenario, savings of 740,000 t CO2 (-34%) can be achieved in 2040 compared to the reference year 2014. In addition, a "forced scenario" was examined in which the implementation rates were chosen as high as possible in order to demonstrate the influence of the tightening of the measures on CO2 savings. The CO2 reductions can thus again be significantly increased to 1.2 million t CO2 (-54 %) and the gap to the derived target of 2040 reduced, but not yet closed. Finally, a "target scenario" was analysed, in which the targeted reduction of CO2 emissions by 70% can be achieved. Here, the expansion of district heating, the increased use of heat pumps and the mixture of renewable gases in the natural gas network were also assumed. However, the assumed developments and resulting CO2 savings are not to be expected under today's framework conditions.
Figure 4 summarises the CO2 emissions for 2014 and the results of the three scenarios.
Figure 4: CO2 emissions from the residential buildings of Munich in 2014 and reduction by 2040 in three scenarios.
The results showed that considerable efforts are needed. Ten action recommendations were derived from the study for the implementation of the Heat Transition in Munich.
Overarching action recommendations:
- create acceptance
- use resources efficiently - achieve maximum CO2 savings as cost-effectively as possible
- ensure competitiveness of prioritized solutions
- think systemically and sustainably
- implement holistically and with foresight
- consider regional particularities
- be open to innovation
Concrete action recommendations:
- Increase the connection rate and contribution of geothermal energy in district heating areas.
- Outside the district heating areas: Replace heating oil, use solar energy and efficiency technologies and raise synergies with area concepts. In addition, an expansion of the district heating area is necessary if the climate protection goals of the city of Munich are to be achieved.
- Targeted renovation of the entire urban area.
- press release: Studie "Wärmewende München 2040 – Handlungsempfehlungen" veröffentlicht
- Article in the SZ from 27.10.2018: Stadtwerke setzen auf Geothermie