District heating Wengen

At a glance

Project facts

Client

Municipality of Lauterbrunnen

Project location

Wengen, Canton of Bern, Switzerland

Business area

BKW Energy Production

Participating BKW company

BKW AEK Contracting AG

Project status

In planning

Implementation period

2025–2030

Service provider

BKW AEK Contracting AG

BKW AEK Contracting AG (BAC) operates under the BKW brand and specialises in the planning, implementation and operation of heat supply solutions for residential buildings and industrial properties.

BKW AEK Contracting AG was formed in 2018 through the merger of the contracting competence centres of AEK Energie AG in Solothurn and BKW Energie AG in Bern. Today, the company has 30 years of experience in heat supply. More than 40 employees take care of the planning, implementation and operation of the systems. The portfolio comprises 40 heat generation plants, including 22 district heating networks.

Lauterbrunnen–Wengen transport line

Distribution grid in the village

Heating oil replaceable per year

CO₂ savings per year

When a proven system reaches its limits

Wengen is one of Switzerland’s best-known holiday resorts. At the same time, the special location of the car-free mountain village places high demands on the supply of energy and infrastructure. Today, the heat supply is largely based on individual oil or pellet heating systems in the properties. Year after year, around 2.2 million litres of heating oil are transported to Wengen by rail and then distributed to hotels, residential buildings and other buildings by small lorries. This system has proven itself over many years. At the same time, new requirements are changing the starting point.

In the long term, the heat supply is to be geared more strongly towards renewable energy sources, the use of fossil fuels reduced and existing infrastructure used more efficiently. Added to this are the particular logistical challenges of a car-free mountain village, where every fuel delivery involves additional effort.

Pellets also do not fully solve the logistical challenge: for the same energy requirement, their transport volume is significantly higher than that of heating oil. A solution was therefore sought that would not only enable the replacement of individual heating systems, but also further develop the heat supply for the entire village centre in the long term. At the same time, it had to meet Wengen’s special topographical, operational and tourism-related requirements and be capable of being integrated into the existing infrastructure.

A solution that makes sensible use of existing resources

At the heart of the project is the decision in favour of an energy concept that combines different heat sources. In regular operation, the heat is to come mainly from the waste heat of the Lauterbrunnen wastewater treatment plant (WWTP) and a new woodchip heating plant. An additional peak-load heating system is planned for exceptionally cold days. A redundant heating plant in Wengen will also increase security of supply.

The choice of this concept is not based solely on technical considerations. The aim is to use existing resources as efficiently as possible while establishing a heat supply that can be operated over the long term and further developed as needed. The district heating network is initially intended to enable the basic expansion in the village and then be gradually densified. This will ensure that the infrastructure remains connectable for future developments too.

Another important basis for the project is close coordination with the municipality of Lauterbrunnen. The existing wastewater pipeline between Lauterbrunnen and Wengen dates from the 1960s and will need to be renovated in the coming years. This creates an opportunity to coordinate the construction of the new transport pipeline with the renewal of the existing infrastructure. If both projects are implemented together, construction work can be coordinated and the associated disruption for residents and guests reduced.

In this project, responsibility is therefore evident not only in the subsequent energy supply, but already at the planning stage. Technical, economic and operational requirements are being coordinated so that a solution can be created that can stand the test of time.

Working together to create the conditions for a new heat supply

The implementation of the project requires the interaction of a wide range of stakeholders. The municipality, landowners, the hotel industry and BKW are working together to create the conditions for the district heating network. BKW is responsible for the planning and construction of the energy centre and the district heating network. This includes, among other things, the transmission pipeline between Lauterbrunnen and Wengen, the pipeline network in the village, the building connections, and the installation and commissioning of the heat transfer stations in the individual properties. Collaboration with building owners plays a central role in this. Around 120 to 150 properties could be connected to the network in the future. The involvement of hotels is particularly important, as they account for a significant share of the village’s heat demand. Numerous heat supply contracts are already in circulation. After signing the contract, owners are given a five-year transition period to gradually replace existing fossil-fuel heating systems and prepare for connection to the district heating network. Implementation will take place in stages. Following completion of the project planning and official approvals, construction of the heating centres and the transmission and distribution pipelines is planned. The first heat is expected to be supplied from 2028; by summer 2030 at the latest, the connected properties should be supplied via the new district heating network. Waste heat from the Lauterbrunnen wastewater treatment plant and wood chips will form the central heat sources. Further densification of the network is planned thereafter.

Infrastructure with a long-term impact

With the district heating network, Wengen is creating the basis for a heat supply designed to meet the requirements of the coming decades. The project aims to significantly reduce the use of fossil fuels while also using waste heat from the Lauterbrunnen wastewater treatment plant and wood chips for heat supply. According to current plans, compared with today’s heat supply, up to 1.8 million litres of heating oil per year could be replaced in future and CO₂ emissions reduced by around 4,900 tonnes annually. At the same time, fewer fuel transports should be required in the village compared with today’s decentralised supply, which can reduce traffic congestion. Beyond its ecological impact, the district heating network creates further long-term benefits. The standardised heat supply simplifies the operation of the connected properties, reduces the maintenance effort for individual heating systems and enables the gradual modernisation of existing buildings. At the same time, the network remains expandable and can grow in line with the further development of the village. The project combines existing infrastructure, local resources and partnership-based cooperation, creating a heat supply that will make a long-term contribution to Wengen’s energy future.