Voith Grimsel 4 pumped storage project will play a key role in supporting Switzerland’s energy transition, with Voith awarded a contract by Kraftwerke Oberhasli AG (KWO) to deliver critical infrastructure for the new facility.
The project includes the supply and installation of two variable-speed pump turbines, each with a capacity of 70 MW, alongside associated motor generators. The new units will expand pumping and generation capacity at the Grimsel site, strengthening the country’s ability to store and balance renewable energy.
Voith Grimsel 4 pumped storage project strengthens renewable energy integration
As countries accelerate the shift towards low-carbon energy systems, pumped storage hydropower is increasingly recognised as a vital enabler of renewable energy integration. Facilities like Grimsel 4 provide large-scale energy storage, helping to balance fluctuations from intermittent sources such as wind and solar.
The use of variable-speed technology allows greater operational flexibility, enabling more precise control of power generation and pumping. This improves grid stability while maximising the efficiency of renewable energy use.
Expanding Switzerland’s low-carbon energy infrastructure
Switzerland already relies heavily on hydropower, but expanding pumped storage capacity is becoming essential as the energy system evolves. Grimsel 4 will enhance the country’s ability to store surplus renewable energy and release it during periods of high demand.
The project also represents the first major new-build collaboration between Voith and KWO, with both companies highlighting the importance of a technically proven design to ensure reliability and minimise risk during delivery.
Ueli Gasser, Project Manager for Electromechanical Installations at Grimsel 4, said the development is an important step in strengthening system flexibility and expanding storage capacity.
Aleksandar Glamoclija, Key Account Manager Germany at Voith Hydro, emphasised the value of the partnership and its role in supporting long-term energy infrastructure development in Switzerland.
The role of pumped storage in the energy transition
Pumped storage hydropower remains one of the most mature and scalable energy storage technologies available today. Unlike battery systems, it can store large volumes of energy over longer periods, making it particularly valuable for balancing seasonal and daily fluctuations in renewable generation.
As Europe continues to decarbonise its energy systems, projects like Grimsel 4 are expected to play a central role in ensuring reliable, flexible and low-carbon electricity supply.
