Switzerland's first large-scale alpine solar power plant

How it works

A solar system in the mountains works in principle like any other solar system. However, there are a few special features in the Alps. These include, for example, the more difficult accessibility, which can make the construction of a solar system logistically more difficult and more expensive. But there are also ad-vantages with solar systems in the mountains.

The most important at a glance:

  • Fewer clouds and fog in the mountains - even in winter 
  • More reflection from the ground due to snow cover in the Alps 
  • Higher efficiency of the solar system thanks to steeper angle of inclination of the PV panels 
  • Better use of the solar system thanks to extra cooling of the solar cells in the mountains 

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You can read more about how a solar system works here.

Pioneer project at a glance

Axpo is planning the first large-scale alpine solar power plant at the Muttsee dam at 2,500 metres above sea level. The dam is part of the Limmern pumped storage power plant in the Glarus Alps and the highest dam in Europe. With this 2-megawatt pioneer project, Axpo is pushing ahead with the expansion of re-newable energies in Switzerland and supplying important winter electricity.

The project envisages a plant with an installed capacity of 2 megawatts and an annual electricity produc-tion of 2.7 gigawatt hours, equivalent to the annual consumption of 600 average four-person households. Around 6,000 PV modules covering an area of 10,000 square metres are planned for this purpose, to be installed on the south side of the Muttsee dam.

The most important facts about the pioneering project:

  • 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.

Winter power from a dam

Switzerland's largest alpine solar power plant to be built at the Muttsee dam

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Alpine solar power in winter

Switzerland produces significantly less electricity in winter than it consumes. Therefore, there is a lack of electricity in winter. And this fact is likely to intensify significantly in the coming years when large-scale power plants are taken off the grid in Switzerland and abroad.

It is important to find solutions to the problem of winter electricity. The large-scale alpine solar power plant in the Glarus Alps makes a contribution here: it supplies 50 percent of its production in winter.

During the winter months, the PV systems in Central Switzerland often lie under a blanket of fog - at high altitudes there is much less fog and thus more solar radiation. In addition, PV systems like to be cold. The efficiency of solar modules is higher at low temperatures. And finally, the sunlight is reflected by the snow cover, which leads to a higher solar power yield. In addition, the angle of inclination of the dam is ideal for solar power production in winter.

The Muttsee dam is interesting for alpine PV for various reasons:

  • Due to its alpine location (almost 2500 m.a.s.l.), photovoltaics is particularly effective there and, thanks to reflection on the snow and little fog, delivers a lot of electricity, especially in winter.
  • The dam has a southern exposure with optimal sunlight
  • The dam has an optimal angle of inclination – snow slips off by itself
  • Existing infrastructure is built on, so no additional open space is occupied
  • Part of the infrastructure (e.g. 16 kV grid connection) already exists

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