Solar energy plugs hydro-electric shortfall in Switzerland

Solar power plants have proliferated since the start of the Ukraine war Keystone / Urs Flueeler

Electricity production in Switzerland is declining because low water levels are reducing output from run-of-the-river hydropower plants. However, abundant solar power generation is helping to prevent supply bottlenecks.

Unlike just a few years ago, solar power is now making a substantial contribution to Switzerland’s electricity supply. This development is largely the result of the rapid expansion of photovoltaic installations since the outbreak of the war in Ukraine.

Small rivers are often reduced to mere trickles, while larger rivers like the Aare, Rhine, and Rhône are witnessing the lowest levels of water since records began. The ongoing drought, without any significant rainfall, has also had a major impact on electricity production. Power plants that use convert the flow of rivers into power are producing considerably less electricity compared to long-term averages.

This is also evident when compared to other exceptionally dry years such as 2003 or 2022. The difference is particularly striking when electricity production is compared to a rainy year like 2016.

The lower electricity production also directly affects energy companies. Repower, the electricity supplier from the canton of Graubünden, writes in response to an inquiry: “In our hydroelectric power plants, electricity production in the months of May to July was around 25% below the long-term average due to the low water inflows.”

Less snow melt

The canton Valais energy company Forces Motrices Valaisannes (FMV) echoed a similar sentiment: “Due to the low amount of precipitation in winter, the snow cover at the end of winter was thin and below the long-term average. This led to less snowmelt and thus a decrease in electricity generation from run-of-river power plants between May and July.”

The same effects are evident outside the Alpine region as well. The Lausanne-based energy company Alpiq reports: “We are experiencing very low water inflows for our river power plants, particularly the facilities (…) along the Aare River.” Alpiq estimates the decline at these plants at around 15 percent compared to the long-term average.

Although the run-of-river power plants are currently supplying significantly less electricity than usual, and the two nuclear power plants Beznau I and II are also offline, there has been no electricity shortage in Switzerland so far.

This is mainly due to the many hours of sunshine. Because the sun shines daily from early morning until late at night, solar power plants produce a lot of electricity.

“Solar energy currently acts as a significant buffer against the unfavourable hydrological conditions in Switzerland. Without the strong expansion of photovoltaics in recent years, the electricity balance would currently be under more strain”, the Federal Electricity Commission Elcom told Swiss public broadcaster SRF.

Growth in photovoltaics

In recent years, the number of solar power systems (photovoltaics) in Switzerland has grown significantly. Consequently, the share of solar electricity has also increased considerably.

“Without this additional contribution, Switzerland would likely have to use more water from the reservoirs for electricity generation, import more electricity or export less, and could also face higher electricity prices,” stated Elcom, which oversees electricity supply in Switzerland.

Solar power plants help to conserve water in the pumped-storage reservoirs. This water is primarily used for electricity production before sunrise and after sunset, when the solar power plants are no longer generating electricity.

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Translated from German, reviewed by an English Department journalist.