Alpine solar plant in Switzerland. Axpo plans to install the first large-scale, alpine solar plant in Switzerland on the Muttsee dam at the Limmern pumped storage plant. With the 2-megawatt pioneer project, Axpo is driving forward the expansion of renewable energies in Switzerland. The plant will generate about half of its power production during the winter – when there is generally a power shortage.

The Muttsee dam is extremely well suited for a photovoltaic plant thanks to its existing infrastructure, its location and its altitude.
The plant will deliver about half of its power production during the winter – a comparable plant in Central Switzerland generates only one quarter of its total production volume during the winter.

Axpo has requested the SFOE to include the pioneer facility at the Muttsee in the list of lighthouse projects
The project “PV Muttsee” foresees a plant with an installed capacity of 2 megawatts and an annual production of 2.7 gigawatt-hours. Some 6,000 PV modules will be installed on a surface of 10,000 square metres. Axpo will submit the building permit application in the upcoming days.

“The Muttsee dam is extremely well suited for photovoltaics,” says Christoph Sutter, Head of New Energies at Axpo. “We have the existing infrastructure with a grid connection and the dam has a southern exposure with optimal sunlight. Furthermore, the plant is located at an altitude of 2500 metres and will deliver a great deal of power, especially during the winter months.”

In contrast to plants in the lowlands, alpine photovoltaic plants generate about half their power production during the winter half-year. There are various reasons for this:
– There is less fog at higher altitudes and there is more solar radiation.
– The efficiency of PV modules is higher at low temperatures.
– Sunlight is reflected by the snow cover resulting in a higher solar power harvest during the winter.

The solar project on the Muttsee dam is unique in Switzerland and a trailblazing undertaking
As a result, Axpo has requested the SFOE to include the facility in the list of lighthouse projects. Axpo is currently in negotiations with potential partners that are interested in buying the solar power generated at the Muttsee under long-term power purchase agreements.

Winter power shortage: Alpine PV as part of the solution
Switzerland consumes more power than it produces during the winter. This winter power problem will become more acute in the upcoming years, when existing large-scale power plants in Switzerland and abroad are taken off grid. In recent years, renewable photovoltaic production capacities in Switzerland were mainly developed in Central Switzerland (between 2013 and 2017 nearly 90 per cent of expansion was in the area of photovoltaics). However, this expansion does not mitigate the winter power problem. Photovoltaic plants in Central Switzerland generate only about one fourth of their total power production volume during the winter.

Axpo sees potential in alpine photovoltaic plants as a possible starting point to support the Federal Energy Strategy 2050 and, at the same time, to produce winter power.

“We see that it is possible to produce large volumes of power with PV,” says Andy Heiz, Deputy CEO and Head of Assets at Axpo. “Of course, the plant on the Muttsee dam is not enough to make a significant contribution. Other locations in non-protected areas and with existing infrastructure must be developed. However, that will also require the right political and economic framework conditions.”

– SmartEfficiency is Developer Partner with AXPO Energy Solutions