The Synergie Maurienne electricity union commissioned setec  to oversee the design and construction of the Encombres small hydropower plant. Situated in the Maurienne Valley in Savoy ( Alps mountains, southeastern France), the plant exploits the Bonrieu stream and the sources flowing into the Saint-Bernard stream.


The development comprises numerous intakes and drains. The collected water is taken by a 4 km long penstock pipe to the plant, equipped with a Pelton turbine capable of handling a 520 L/s flow rate. The plant’s gross power reaches 3.2 MW, with an annual output of 10 GWh.


setec  carried out all the design and construction supervision tasks involved in developing this small hydropower plant, from the study phase (design, geotechnical/topographical management, and the building permit) to the construction phase:  WFD: Water Framework Directive, building contracting assistance, works supervision, scheduling management and coordination, design checks, shop drawings, water intake studies, technical and financial project management, assistance for work acceptance and guarantee of full completion, and assistance for the service launch.


setec  worked with Synergie Maurienne up to the service launch and the first months in operation.




Key figures

Period of services

September 2012 – December 2015

Key challenges

The pipe crosses a 300 m zone moving by 2-3 cm annually. The solution chosen was a pipe enabling angular deviations in line with the horizontal landslide. A tubing and sleeve system was also planned to extend the pipe in the unstable area.