Improving hydropower through long-range drought forecasts

Das Bild zeigt den Stausee des Lac de Moiry im Kanton Wallis.

Researchers at the Swiss Federal Institute for Forest, Snow and Landscape Research (WSL) have developed a hydrological model for forecasting dry spells lasting several weeks.

Changing climatic conditions pose extra challenges for hydropower plant operators. As part of the National Research Programme “Energy Turnaround” (NRP 70), researchers at WSL, MeteoSwiss and ETH Zurich have now developed a complex hydrological model that enables spatially detailed forecasts of persistent dry spells using real-time data. This allows reliable predictions of water scarcity over a period of up to three weeks.

Drought is easier to predict than precipitation, which can only be reliably forecasted up to five days at most. But dry spells are complex phenomena that depend on numerous climatic processes and regional factors such as intensity of water use, soil storage properties, expected soil moisture, water runoff and underground water reservoirs. Previously, Switzerland had no system capable of monitoring these local variables efficiently.

It is in society’s interest that hydropower plants be able to predict the availability of water and convert the stored water into electricity when market demand is high. Only when hydropower plants can operate profitably even under changing climatic conditions will it be possible to finance modernisation and expansion, as envisaged by the Energy Strategy 2050, from their own resources.

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