Pioneer project above the fog line

Axpo and IWB are building the largest alpine solar plant at 2.500 metres above sea level on the Muttsee dam. Denner will buy the alpine energy for 20 years. With the 2.2-megawatt pioneering project, Axpo and IWB are driving forward the expansion of renewable energies in Switzerland and supplying important winter electricity.

A solar plant with almost 5,000 photovoltaic modules will be installed on the dam in the Glarus Alps. The plant will produce approx. 3.3 gigawatt-hours of electricity per year – corresponding to the consumption of 740 four-person households. The solar plant will cover a surface of 10,000 square metres, which corresponds to the area of 1.5 football fields. The dam is part of the pumped storage plant Limmern in the Glarus Alps and is the highest situated dam in Europe.

Contribution to winter power

The alpine location makes the solar plant particularly efficient. It will generate half of its production during the winter half-year because of its location above the fog line and the high sun exposure. In addi-tion, solar plants like the cold. The efficiency of PV modules is higher at low temperatures. The high alti-tude is also favourable for the so-called "Albedo effect": Sunlight is reflected by the snow cover and results in higher solar power production.

Optimally situated

The southeast/southwest position is also advantageous for the construction of a solar plant on the Muttsee dam, allowing optimal use of sunlight. A further advantage: Thanks to the existing infrastructure belonging to the Limmern pumped storage plant, additional grid expansion is unnecessary and no additional open space will be needed for construction.