Low river levels threaten Bavarian hydropower output

Record-low river levels are reducing hydropower production in Bavaria, but increased solar generation and the wider European electricity market mean a power shortage is not expected, BR reported.

At the gauge below the hydropower plant in Gersthofen, the Lech is more than one metre lower than usual for this time of year. Only two of the plant’s five turbines are currently operating.

Lars Leifeld of Lechwerke said the situation was exceptional because May through August are normally the wettest and most productive months. He expects output to fall by about 30 percent this summer.

Hydropower accounts for 22.1 percent of electricity production in Bavaria, compared with 4.7 percent nationwide. A decline therefore has a greater impact in Bavaria. Overall, however, 75 percent of the state’s electricity production came from renewable sources in 2024. Solar power accounted for 29 percent, wind power for 8.5 percent, biomass for 15.2 percent and other renewable sources, including geothermal energy, for 0.9 percent. Natural gas was the most important conventional source, at 19.8 percent.

Leifeld said the recent expansion of solar power reduced the risk of shortages because photovoltaic systems were currently operating at full capacity. He also pointed to the European electricity market, where countries can support one another.

Hydropower helps balance the grid

Hydropower remains important for stabilising the electricity grid, even during dry periods. Production can be adjusted relatively quickly by opening or closing sluices when demand changes, such as when lights are switched on at dusk or a large industrial consumer is turned off. Gas-fired power plants cannot increase or reduce their output as quickly.

The plants also help maintain water levels during the drought by impounding water. Leifeld said operators allow only as much water through as flows in from upstream.

Environmental effects remain disputed

Water ecologist Manfred Holzner views the overall approach critically. In natural river courses, more water could seep into the soil and create a natural water store, he said. But in the lower reaches of rivers, he added, it was already too late to restore those conditions. Because of settlement and agriculture, there is no longer enough space for many rivers to return to a natural course.

Erosion is another problem in Bavaria’s waterways. Straightening and construction work have made water flow faster, washing sediment from riverbeds and causing river channels to cut increasingly deeply into the landscape. Holzner said many weirs and hydropower plants had been built to slow this process and raise water levels through impoundment.

The Bund Naturschutz environmental group argues that impounding rivers fundamentally changes the character of Bavaria’s mountain rivers and deprives native species of their habitats.

Holzner recommends giving rivers more space and restoring water to floodplains, particularly in upper reaches where this is still possible. In lower reaches such as the Lech near Gersthofen, higher floodplains have long been cut off from natural water supplies. There, he said, impoundments are necessary, and generating carbon-neutral renewable electricity from hydropower can also make sense.