Power increase of Lavey (Switzerland), hydroelectric power scheme, Lavey+ project

Abstract

Lavey Hydroelectric Scheme is located in the French-speaking part of Switzerland. It was commissioned in 1950. Since then, and under an operating lease of 80 years, it produces about 400 GWh per year, covering 32% of the electricity needs of the City of Lausanne. At the start of the last decade, further to the political commitments (Energy 2050), Switzerland turned mainly to renewable energies. The City of Lausanne and its Public Utility, which produces and distributes electricity to more than 230'000 homes, have developed a project, called Lavey+, to increase the power and energy generation at Lavey power plant. Within the framework of the Lavey+ project, it was decided in 2008 to improve the present situation and to study the realization of a new water intake, a second headrace tunnel parallel to the existing one, to expand the present underground cavern, to put a fourth Kaplan turbine generator and to modernize the plant. To ensure a better operational flexibility, it is planned to connect the new gallery also to the third turbine, which is already in operation. Additional studies were also performed to improve the area of the reservoir in order to improve the conditions of bed load material transit. After more than 60 years of interruption, it was decided also to restore the passage of the fish fauna in the upstream and downstream migrations. Finally, a proposal to reassess the ecological flow, which would be annually modulated downstream from the dam, was made.