High-Alpine Photovoltaic Plant "Gletschersolar Matterhorn"

The future of energy in Switzerland is increasingly shaped by innovative solutions aimed at reducing the country’s dependence on imported electricity during the winter months. With the launch of the “Solar Express” by the federal government, the share of renewable electricity produced domestically during the cold season is set to increase significantly. One of the most promising options is to harness the intense solar radiation in alpine regions, where higher irradiation levels and reflection from snow and ice provide exceptional solar potential. Gruner is proud to have contributed to the development of the alpine solar project at Trockener Steg in Zermatt.

Translating this enormous potential into a viable project, however, involves technical challenges. Gruner was commissioned by Axpo to identify suitable areas for an alpine solar installation around the retreating Upper Theodul Glacier in Zermatt. The rugged terrain at Trockener Steg is characterized by steep slopes, uneven ground, and sensitive ecological conditions. Protected areas had to be excluded, avalanche and snow risks carefully assessed, wind forces considered, and orientation optimized for maximum energy yield without compromising feasibility.

Gruner’s mapping and evaluation resulted in only a limited number of potential areas meeting all requirements. This demanded a balancing act between maximum installed capacity and realistic implementation. The arrangement of the solar tables was developed in consideration of these constraints, following natural contour lines to respect the terrain while minimizing costs and logistical challenges.

Furthermore, Gruner supported Axpo in the structural design of the solar tables, taking into account extreme alpine conditions. At elevations above 2897 meters, where heavy snow and wind loads are expected, standard solutions were not suitable. Instead, based on the NalpSolar project, the support structures have been adapted to the specific conditions of the Trockener Steg site. They consist of steel frames fixed several meters above ground level, designed to support photovoltaic modules and optimize their production in this alpine environment. The project foresees an installed capacity of 7.7 MWp.

This configuration is expected to generate around 12.6 GWh annually, with a specific winter production of 571 kWh/kWp. These values exceed the minimum requirements of the “Solar Express” program. In addition, Gruner identified additional areas that could be developed in the event of land losses later in the project, for example due to environmental impacts, providing the project with greater flexibility.

Construction at this high-alpine location at Trockener Steg presents additional challenges due to climatic conditions, which allow work only during the summer months. Gruner’s planning therefore included a sophisticated logistics concept for material transport.

As part of the project development, the documentation required for the building permit application was also prepared. These documents demonstrate to the authorities the technical feasibility of the project, compliance with the applicable requirements, and the planned implementation under the specific alpine conditions.

The Solar Express is about rethinking how and where we produce energy. The alpine solar project at Zermatt is a prime example of this new approach. Together with Axpo, we are proud to strengthen Switzerland’s winter electricity supply and to demonstrate that even the most challenging terrain can be transformed into a sustainable energy source.

We are honored to have brought our expertise to this milestone project, and we look forward to following its development as it becomes a beacon of Switzerland’s clean energy future.

For more information on this project, please visit Zermatt Bergbahnen AG’s website (in german). 

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