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Axpo and IWB to build Muttsee solar plant; Denner to use the electricity


Axpo and IWB are jointly implementing the largest alpine solar plant in Switzerland. The partners will install and commission the pioneering 2.2 MW Muttsee dam project this summer. Supermarket chain Denner will draw on the solar electricity it produces for 20 years.

  • Energy suppliers Axpo and IWB have formed a partnership to develop the 2.2 MW plant.
  • Denner is participating in this project as part of its sustainability strategy and has committed to take the alpine solar electricity for 20 years.
  • The alpine location means that the plant produces plentiful electricity, even in the winter months. And as it is being installed on an existing dam, it is particularly environmentally sound.


AlpinSolar: achieving more together

Originally initiated by Axpo, the large-scale alpine solar plant on the Muttsee dam is now the ‘AlpinSolar’ cooperative project by Denner, Axpo and IWB. The two energy companies Axpo and IWB are establishing the plant through a partnership. Denner, the largest discount supermarket chain in Switzerland, will draw alpine solar electricity for 20 years. The initiative is consistent with Denner’s ambitious sustainability goals.

Denner CEO Mario Irminger explained: “This project reaffirms our commitment to reaching our climate goals. Our aim is also to only draw our electricity from renewable sources, which is why we support innovative solutions that promote the responsible use of natural resources. With the alpine solar plant, we are investing in our future and strengthening Switzerland as a production location.”

‘AlpinSolar’ is exactly the kind of plant that the energy transformation requires. The solar plant on the Muttsee dam will be constructed under environmentally sound conditions and will supply plenty of renewable electricity – particularly in winter. What is more, the project itself is particularly environmentally friendly because the plant will be built on an existing dam.

Axpo CEO Christoph Brand said: “Unfortunately, the lack of a regulatory framework means that this type of plant is barely economically feasible, as is the case with this project. Nevertheless, we have chosen to carry out this flagship project with our exceptional partners to make a statement and push Switzerland’s energy transformation a step further. We also see the project as an important contribution to the discussion around the forthcoming legislative amendment.”

IWB, the energy supplier for the canton of Basel-Stadt, has a 49-percent stake in the project. The company consistently strives for a climate-friendly energy supply. “This includes the expansion of electricity production from solar energy with targeted investments in Switzerland,” said IWB CEO Claus Schmidt. “So AlpinSolar is a great fit with our strategy.” Planeco, an IWB subsidiary, will construct the plant.

Plenty of solar power – even in winter

The 2.2-megawatt solar plant will be constructed 2,500 metres above sea level on the Muttsee dam, part of the Limmern pumped storage plant, and will produce around 3.3 million kilowatt hours of electricity per year. Almost 5,000 solar modules will be mounted on the dam, which has an optimal south-facing orientation. The alpine location means that the Muttsee plant will deliver half of its production during the colder half of the year – a time when the sun is generally in short supply in Switzerland. This contrasts with solar plants at lower elevations that only produce around a quarter of their electricity production during this half of the year. The solar plant will be constructed on Muttsee and commissioned in summer 2021.

About Denner: Denner is Switzerland’s leading discount supermarket with a presence as a local supplier in every rural and urban region of the country – everywhere that customers live and work. Denner offers a comprehensive range of products for everyday requirements at over 820 locations. In 2020, the discounter employed a staff of over 5,500. To ensure that this growth did not come at the expense of the environment, Denner set ambitious goals in its sustainability strategy, investing in innovative projects to drive responsible action both internally and externally.

About Axpo: Axpo is Switzerland’s largest producer of renewable energy, as well as an international leader in energy trading and the marketing of solar and wind power. Its 5,000 employees combine experience and expertise with a passion for innovation. Axpo uses state-of-the-art technology to develop innovative energy solutions for its customers in 30 countries in Europe, North America and Asia.

About IWB: IWB is the company for energy, water, mobility and telecommunications. It is a committed, competent and reliable supplier to its customers in the Basel region and beyond. IWB is a leading service provider for renewable energies and energy efficiency. The company strives for a 100% renewable power supply that enables the climate-friendly, efficient and economical handling of energy. In its own plants, IWB already produces more renewable electricity than is required by its customers in Basel. IWB makes targeted investments in infrastructure and develops new business models.

Grazia Grassi
T +41 44 455 11 51

Corporate Communications
T 0800 44 11 00 (Switzerland),
T +41 56 200 41 10 (International) 

Erik Rummer
Head of Corporate Communications
T +41 79 758 54 69

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