District heating in Thun: energy from waste incineration
Every year, 130,000 tonnes of waste are incinerated at the Thun wasteto- energy plant. Providing waste heat in the form of district heating, among other things, makes ecological sense, explains Andreas Santschi from eicher+pauli Bern AG, which played a key role in the development of the heating network in Thun. To ensure the heat could be recovered economically, the KliK Foundation’s support was essential.
The district heating network came into operation in Thun North in 2018 and in Thun South in 2021. The operators of the system, which has approximately 35 kilometres of pipelines, are Fernwärme Thun AG, AVAG Umwelt AG as the heat generator, and the regional energy suppliers NetZulg AG and Energie Thun AG. The network is constantly being expanded.
The environmentally friendly district heating replaces oil and gas heating systems beyond the municipal boundaries. Simultaneous production of electricity and heat in the Thun waste-to-energy plant means that the energy content of the combustible waste is utilised optimally – efficiency is high, resources are conserved and dependence on fossil energy carriers is comparatively low. Expansion of district heating makes a decisive contribution to the climate targets of the city of Thun, which aims to become climate-neutral by 2050, and thus to the sustainability of the entire region.
Water heated to 130°C is distributed throughout the region from the central plant via three district heating loops. After use, the water returns to the central plant, where it is reheated. (Source: fernwaerme-thun.ch)
Big investments, big savings
Extensive investment was required for the project’s implementation. In terms of construction, this primarily involved the expansion of the pipeline infrastructure with main and distribution lines, house connections, energy centres and transfer stations. The Thun district heating network currently saves around 22,000 tonnes of CO₂ emissions per year (compared to burning the amount of heating oil that would conventionally be required to generate the same amount of heat) – and the trend is rising. The annual payment of subsidies per tonne of CO₂ not emitted gave the project the planning security it needed.
Plenty of added benefits for customers too
A connection to a district heating network also offers advantages for consumers. Connected buildings benefit from extra space, as the installation of a heat exchanger takes up very little room, so additional cellar space, where an oil tank may have previously stood, can now be used as a hobby room or wine cellar. Homeowners who heat with district heating do not have to worry about buying oil or gas. Fuel deliveries, firing inspections, maintenance work, burner services and tank cleaning are no longer required. And last but not least, unlike gas pipes and heating oil tanks, with district heating there is no risk of fire or explosion.
Logical and necessary funding
For Andreas Santschi from eicher+pauli, it is clear that funding from the KliK Foundation is essential to ensure that the Thun district heating project can be operated professionally and economically in the long term. In fact, many of today’s successful heating networks could only be created and expanded with financial assistance from the supported programme. There are plans to extend Thun’s district heating network in future to the Seefeld and Dürrenast neighbourhoods and around the Bahnhofplatz square.
We would like to thank Andreas Santschi, Senior Project Manager at eicher+pauli Bern AG, and Dominic Zysset, Managing Director of Fernwärme Thun AG, for their cooperation.