Today, only a few cities have a clear vision of decarbonizing their heat supply within the coming decades. In Baden-Württemberg (SW Germany), a new climate protection law obliges 103 municipalities to draft their vision of a fossil-free heat supply by 2050 by developing a roadmap. These cities are home to 5.5 million people, i.e. half of the state’s population. The parliament finally adopted the amendment to the state’s climate protection law from 2013 on October 14th, 2020.
With this amendment, Baden-Württemberg paves the way towards a carbon-free heat supply of the cities.
Development of a regulation framework
The amendment’s cornerstones were discussed already in 2018, but the political process was somewhat lengthy. In the end, it took almost two years to achieve an agreement for the regulations. From an energy efficiency point of view, these are the most important topics:
- Compulsory municipal heat planning for all cities with more than 20,000 inhabitants: (energy needs, potentials to reduce the energy consumption, potentials of renewable energies and excess heat, necessary areas, strategy for implementation).
- All 1,100 municipalities in Baden-Württemberg are required to submit their data on the energy consumption of the municipal building stock to an online database. This requirement intends to push municipalities towards effective energy management.
- PV will be required on all new non-residential buildings and parking lots for more than 75 cars from 2022 onwards.
- Climate mobility plans are introduced for cities.
- A tool to foster sustainable construction will be implemented in all grant schemes.
Implementation of municipal heat planning
If the transition towards a carbon-free heat supply shall be successful, municipalities need a clear and individual strategy. This strategy must be local; local boundary conditions must be considered.
In the first step, the status quo of energy consumption must be analyzed. This information already forms a valuable basis for the heat demand of the residential buildings. The amendment explicitly allows municipalities to gather heat consumption data, i.e., data from utilities or chimney sweeps, who own a good database of all installed heating systems. Such data is essential to get a proper image of the current situation of the heat supply.
The next step covers the analysis of the potential to reduce energy demand and supply fossil-free energy. Depending on the age and type of the building, thermal insulation can be applied. Depending on the structure of the companies in the city, the potential to use excess heat is different. The use of renewable energies mainly depends on the available space, i.e., for large solar thermal and PV installations close to the municipality, and the access to environmental heat sources.
Based on the status quo and the potentials analysis, a scenario for the whole city’s CO2-neutral heat consumption is then developed. It covers the demand for residential buildings and the need for industry, including process heat. Boundary conditions concerning the availability and price of green electricity and green gas also have to be observed. As a result, the municipality obtains a city map, showing neighborhoods suitable for district heating, areas for heat pumps, and some buildings where biomass is an appropriate energy source. In any case, we expect the potential for district heating to be severalfold of today’s level.
The final step of the planning process is a local strategy for the transition of the heating sector. How will the city reach its targets within the given 30 years? This transformation strategy describes concrete measures necessary to become carbon neutral by 2050, at the latest. The cities have to finalize their plans by the end of 2023, and later update those plan in 7 years periods.
The full article was published in Hot|Cool – the International Magazine in district heating and cooling No. 4/2020 of the Danish Board of District Heating (DBDH).
Cover picture: Ministry of the Environment, Climate Protection and the Energy Sector, Baden-Württemberg