Modernising hydropower plants: variable speed (FSFC) at Z'Mutt pumped storage plant (Switzerland)

Z’Mutt is a pumping station located in Canton Valais, Switzerland, and feeds water into the main reservoir of the Grande Dixence hydroelectric scheme. Originally commissioned in 1964, Z’Mutt has a total pumping capacity of 88 MW across five existing pumps. As part of the XFLEX HYDRO project, one unit will be replaced with a new 5 MW variable speed reversible pump-turbine which, when installed with modern power electronics and smart controls, will demonstrate a high range of flexibility. This enhanced capability will allow the power plant to produce electricity and improve the quality and reliability of power of the grid it is connected to. Along with the six other XFLEX HYDRO power plants, Z'Mutt is set to become a landmark in the energy landscape, showcasing how innovation can help our power systems accommodate an increasing amount of intermittent renewable energy, including wind and solar. This modernisation project is part of the European Union-funded project XFLEX HYDRO. XFLEX HYDRO power plants are designed to be more flexible than traditional power plants and provide a range of services to ensure that local and regional power grids remain reliable and resilient to current and future energy supply disruptions. Partners of the project include: Alpiq (Swizterland), Andritz, Armines, CEA, EDF (France), EDP (Portugal), EPFL, GE, HES-SO, International Hydropower Association, INESCTEC, Mines Paris Tech, NEW by EDP & CTG, Power Vision Engineering, SuperGrid Institute, UPC, University of Stuttgart, Voith, Zabala. The project has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 857832 For more information: www.xflexhydro.com TIMESTAMPS 00:00 Introducing Z'Mutt hydropower plant 00:23 A new reversible variable pump turbine 00:39 What determines the amount of power used by a pump? 00:53 Rotation speed: the only way to modulate the power of a pump 01:17 Full-size frequency converter 01:41 Other advantages of the variable speed turbine solution 01:56 Reducing damage with variable speed 02:26 1D validation numerical model for variable speed technology 03:35 Reduced scale model testing 04:20 An overview of expected benefits