Strong winter yields Solar plants in the mountains deliver more electricity than expected
The first alpine solar plants in Switzerland exceed expectations. Certain designs and module variants are more convincing than others, as there is also a negative example.
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- The alpine solar plants in Sedrun GR, Grengiols VS and others generated more electricity than forecast last winter.
- The winter of 2023-24 was particularly snowy and had few hours of sunshine.
- However, after two winters, the solar installation at the Muttsee dam has suffered considerable damage to some of the modules.
How much electricity do alpine solar plants really generate? Do they really use their location above the winter fog as hoped? Or does the snow throw a spanner in the works?
There are still only a few systems and they have not been in operation for very long. But they are now providing the first reliable data. And these are more positive than predicted, as the Tages-Anzeiger newspaper has investigated.
The Sedrun Solar plant generated 4 percent more electricity than those responsible had calculated - despite the snowy winter of 2023-24, in which the sun shone less than the long-term average. The panels generated 46 percent of their first annual yield in the winter half-year from the beginning of October to the end of March.
Alpine solar systems exceed federal target
The federal government sets a target yield of 500 kilowatt hours per 1000 kilowatts of installed capacity for a system to receive financial support. A solar power system that can generate a maximum of 1000 kilowatts of power due to its modules must achieve at least 500 kilowatt hours in the winter half-year. Sedrun clearly exceeds this value with 780 kilowatt hours in its first season.
The test plant in Grengiols VS is also exceeding expectations. Various modules are being used there, including bifacial modules that can absorb solar radiation on both sides. Last winter, these generated 25 percent more electricity than monofacial PV panels. With 650 kilowatt hours in winter, this test system also easily met the federal threshold.
According to the company, three of Alpiq's alpine solar plants also achieved the federal government's yield target - although the one in Gondo VS was particularly unfavorably located in terms of solar radiation and snow accumulation.
Failure at the Muttsee dam
There are also plants that do not meet expectations, such as the one at the Muttsee dam. Of its 5000 modules, 270 were broken after two winters and had to be replaced, as reported by "Südostschweiz".
Unlike at the dam, the modules in Sedrun are mounted on stands three to four meters above the ground. This means that the modules remain free of snow even when the wind transports and accumulates large quantities, the Tages-Anzeiger quotes the operating company Energia Alpina. Only a snowfall event, which occurs every 50 years, could damage the modules at certain points, admit those responsible.
Energia Alpina is working with a company that builds avalanche barriers to construct the system. This suggests a great deal of experience with how a system must be designed in order to withstand large amounts of snow.
A representative of Aeesuisse, the umbrella organization of the renewable energy industry, said that the measured winter yields were encouraging and showed how great the potential of Alpine solar systems is for supplying electricity in winter.