Alpine PV plants outperform lowland counterparts in winter, study finds

Alpine solar installations can produce up to four times as much electricity during the winter half-year as installations in the lowlands, the Zurich University of Applied Sciences (ZHAW) said on Tuesday, citing research data.

The conclusions are based on measurements conducted over the last five years by the university at a pilot installation in the Davos-Parsenn skiing area in the Swiss Alps.

The test facility, situated at an altitude of 2,500 metres (8,202 feet) above sea level, generates three to four times more electricity from October to March than an installation in the lowlands. According to ZHAW researcher Juerg Rohrer, the particularly high yields in April and May are also a significant advantage for alpine solar systems.

The research further shows that alpine installations are most effectively placed on south-facing slopes with a southern orientation of the modules. If the modules are inclined between 60 and 90 degrees, losses due to potential snow cover are negligible, as the snow slides off. Vertical modules with a 90-degree tilt angle achieve higher yields in December and January. Modules with a 60 or 70-degree tilt angle, however, are more productive between March and May and during the summer.

The research data are being published as Switzerland is encouraging the construction of new alpine solar systems to secure energy supply in winter months. Under the so-called Solar Express initiative, a large number of installations are already being planned.

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