A new hydroelectric power plant tested on a 1:30 scale

The availability of electricity is a pressing social issue, as the recent energy debates show. Fifty-seven percent of the electrical energy produced in Switzerland is hydraulically generated. The pumped storage system used by FMHL (Forces Motrices Hongrin-Léman) makes it possible to store energy, produced for example from wind turbines and solar sources, like a battery. Thus when the energy demand is low, the Veytaux power plant pumps the water from Lake Geneva to the Hongrin reservoir where it is temporarily stored in order to be reversed later by turbines to produce the electricity when the demand rises. The new power plant Veytaux 2 will enable the power of the existing installation to be doubled from 240 to 480 megawatts.

To fit this new underground power plant, with a volume equivalent to Lausanne cathedral (140,000 m3) into the existing system, it was essential to study the functioning of the hydraulic circuit downstream using a physical model. The Hydraulic Constructions Laboratory was commissioned to complete this study. Anton Schleiss’s team has reproduced the two Veytaux power plants on the 1:30 scale in its hydraulic machine hall. The physical model comprises the water supply point in Lake Geneva, the old and the new factory with their two pump-turbine groups, and the outlet channel. It has all been designed to simulate the functioning of the new power plant that will be put into operation in 2014. “We can test the interactions between the two power plants, study how they function in borderline cases, anticipate problems that may arise and make our recommendations”, points out Martin Bieri, an engineer at LCH who is working on this project with Giovanni de Cesare and Stéphane Terrier. The first testing phase is complete, and the operation of the largest hydroelectric construction site in the Vaud canton was launched on 7 April.

The two Veytaux power plants

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