Exploring multifunctionality in hydropower

Professor Reynard and his team at the University of Lausanne are deeply engaged in researching the multifunctionality of alpine hydropower infrastructure. ” Most dams in Switzerland were built for a single purpose: to generate power,” he explains. However, over time, these reservoirs have been granted additional uses, such as irrigation, drinking water supply, artificial snow production, and flood protection. “We’re studying the multifunctionality of the alpine dams from different angles: the history of the multiple uses of water, when the new uses emerged, the perceptions of the role of water and energy by different stakeholder groups, as well as institutional aspects of multifunctional water management, in particular the role of concessions,” Reynard added.

The Gornerli hydropower project: A multifunctional marvel

The Gornerli project stands out as the largest and most significant among Switzerland’s 16 Hydropower Round Table projects. ” This project clearly has great potential for energy production due to the vast volume of water in the catchment area,” says Professor Reynard. ” It also plays an important role in managing hydrological risks in the Matter Valley. It serves as a drinking water and irrigation reserve for the municipalities of Zermatt, Täsch and Randa. As the structure is incorporated into the Grande Dixence storage power plant, it could supply Lac des Dix with water.”

Enhancing hydropower generation

The Gornerli project is set to enhance Switzerland’s hydropower capabilities significantly. “The water from the new lake will be pumped into the main Grande Dixence collector, so there’s no need to build a new power station,” Reynard notes. Currently, 146 million cubic meters of water flow in from the Gornera, with 115 million cubic meters diverted to the Z’Mutt plant. The new dam will allow all this water to flow into the Grande Dixence, contributing significantly to winter energy production. The Gornerli dam alone could produce a third of the additional winter electricity envisioned by the Hydropower Round Table projects.

Crucial flood protection

Beyond energy, the Gornerli project is vital for flood protection in Zermatt and the Matter Valley. Reynard explains how Zermatt’s urbanization makes it highly vulnerable to flooding: ” Peak flooding during thunderstorms, intense snowmelt or the sudden, uncontrolled discharge from an underground glacial lake, as happened with the Triftbach in July 2019, pose a major risk to the town. The construction of a reservoir upstream would act as a retention structure, thus reducing the risk.”

Adapting to climate change

As glaciers continue to melt, ensuring a secure supply of drinking and process water becomes increasingly critical. “The construction and networking of water reservoirs is one of the keys to adapting water management to climate change,” says Reynard. ” Due to their large capacities, alpine reservoirs constitute important infrastructure for the integrated management of water resources.

“With this in mind, the construction of a new reservoir near Zermatt can only have a positive impact on integrated water management. But we must not forget that true integrated management not only needs to ensure a long-term water supply, but also optimise the demand for water, in particular through organisational measures and water savings. “

About the hydropower project

The Gornerli hydropower project is the largest from the hydropower round table as it would supply 650 GWh of additional winter energy and 200 GWh of additional production – enough to supply around 140,000 households with electricity for a year. This means it would be able to supply a third of the additional hydropower needed in Switzerland during winter by itself. The project is implemented by Grande Dixence AG, in which Alpiq is the majority shareholder. The municipality of Zermatt, the municipalities of the Matter valley, all other concession municipalities of the Grande Dixence and other partners are all closely involved in the project and are in favour of it.

Source: Alpiq