Tettnang: A green local heating network for the municipal heating transition

A guest article by Michael Hofmann, Managing Director of Regionalwerk Bodensee.

The town of Tettnang in Baden-Württemberg is taking the municipal heating transition into its own hands and will be the setting for a pioneering project in the coming years: in close partnership between Regionalwerk Bodensee and ENGIE Deutschland, a local heating network based on renewable energies is being created that will set new standards for a sustainable heat supply. Right from the planning phase, this project impressively demonstrates how technical expertise and local cooperation can lead to a sustainable and climate-friendly energy infrastructure.

Project structure: The basis for Tettnang's green heat transition

The vision for Tettnang is clear: a comprehensive municipal heating transition should lead to as many of the town's residents as possible being connected to an efficient and environmentally friendly local heating network. To this end, Regionalwerk Bodensee and ENGIE are initially establishing Wärmeversorgungsgesellschaft Tettnang GmbH. From 2025, this company will construct a 13.2 kilometre-long local heating network with a connected load of around 15 megawatts. In the first phase of the project, 14 public buildings in the town are to be connected to the network, including a school complex, the New Castle and the town hall. The contract with Tettnang is designed for a period of 20 years. During this time, further residential and commercial areas will gradually be connected to the heating network - and thus benefit from 100 per cent green heating energy.

Technical planning: focus on sustainable energy generation

At the centre of the planned system is an energy centre that will include three biomass boilers at the end of the project. These will provide a total heat output of 5.9 megawatts and will be fuelled by woodchips. Due to their high energy density and regional availability, these woodchips are ideal for the project: they raise the sustainable heat supply to a new level and are the centrepiece of the project's excellent carbon footprint. The biomass heating plant is complemented by an additional gas boiler with a capacity of 3.5 megawatts. This will be used when the biomass plant is undergoing maintenance or when peak loads need to be covered.

Integration and expansion: local heating network as flexible infrastructure

When construction work starts at the beginning of 2025, the local heating network will be integrated into Tettnang's existing municipal infrastructure without significantly disrupting the town's ongoing operations. Initially, the local heating network will supply 18 connected users and will then be successively expanded over the coming years. In this way, it will ultimately provide green heat energy for around 350 public and private consumers. An annual heat supply of around 3.9 gigawatt hours is planned.

Economic and ecological advantages: Sustainability meets stability

The local heating network in Tettnang is an economically attractive model for the municipal heating transition. By utilising regional and renewable energy sources such as wood chips, stable prices can be guaranteed in the long term. This makes the heat supply less susceptible to price fluctuations, such as those that occur with fossil fuels. From an environmental perspective, the project will be a complete success: according to the underlying forecasts, Tettnang will save up to 4,176 tonnes of CO₂ per year when supplying heat. The heating network will therefore make a significant contribution to achieving the climate targets of the town and the state of Baden-Württemberg.

Municipal heat transition in Tettnang: a model for the future

The local heating network in Tettnang is a pioneering project that is not only driving forward the local energy transition, but can also serve as a model for other municipalities. The close cooperation between the town, Regionalwerk Bodensee and ENGIE Deutschland shows how innovative technology and regional resources can make a sustainable and economically viable energy supply possible. The positive ecological effects and long-term economic stability of the project emphasise the importance of such initiatives for a successful municipal heating transition. Tettnang is thus sending a strong signal for the future - for a greener, more liveable and climate-friendly region.