Sion – Forces Motrices de la Gougra SA (FMG) is pressing ahead with the project to raise the Moiry dam, located in the Val d’Anniviers (Canton of Valais). It is one of sixteen hydroelectric projects of national importance selected by the federal government to enhance the security of electricity supply in winter.
After several years of technical, legal and environmental studies, the future profile of the Moiry Dam is taking shape. The preferred option is to raise the dam wall by 9 metres. In a comparison of the various proposals studied, this is the optimal solution in terms of its contribution to the energy supply, technical feasibility, environmental impact and investment costs.
Equivalent to the consumption of 10,000 households
This increase in height would raise the reservoir’s storage capacity by about 15%, corresponding to more than 12 million cubic metres of water, and shift between 40 and 50 GWh of additional seasonal energy from summer to winter. This is equivalent to the annual consumption of around 10,000 households. As a result, the dam would reach a total height of about 157 metres, strengthening its contribution to the country’s energy supply.
In addition to raising the dam, the project also includes a significant improvement in the pumping capacity between the upgraded Mottec plant and the dam. Since the facility was commissioned in 1958, a portion of the water collected at Mottec has been pumped up to Lake Moiry. A new pump will provide 50% additional capacity, at 5 m3/sec. This system provides ideal flexibility to cover fluctuations in consumer demand for electricity. “Raising the Moiry dam increasing the pumping capacity at the Mottec power plant demonstrates our commitment to meeting the country’s current and future electricity needs,” says Michael Plaschy, Chairperson of Forces Motrices de la Gougra.
Dialogue with environmental associations
The environmental impacts of the project to raise the height of the Moiry Dam have been analysed by FMG from the earliest phases of the study, with support from specialist consultants. Once the studies and scope of the project had been clearly established, constructive discussions began in early 2026 with several environmental organisations and angling representatives. The purpose of these consultations has been to present the project to the parties concerned, identify the issues at stake and discuss the methodology for implementing the compensatory measures provided for in law. Future studies will focus on environmental compensatory measures in particular and on the adaptation of existing infrastructure, in close coordination with the cantonal and municipal authorities.
As the level of the lake and top of the dam will be raised by approximately 9 metres, it will no longer be possible for the dam restaurant to continue its operations in its current location. The routing of the access road and a site for a new restaurant are currently being discussed with the municipality.
The Moiry Dam is a core component of the Gougra hydroelectric complex operated by FMG. The project to raise the dam is part of a rationale comprising targeted upgrades to existing infrastructure and aims to optimise the use of the water already turbined. Considered a project of national interest within the context of the Swiss Confederation’s Hydropower Round Table, it could benefit from federal support of up to 60% of the investments, subject to formal decisions following the submission of the building permit. The project has already received a favourable opinion in principle from the six licensing municipalities, acting through the FMG-39 Association of Licensing Authorities.
Planning studies are continuing, as is the preparation of authorisation procedures at cantonal and federal levels. Subject to the completion of these procedures, it is envisaged that work will start in 2029.
For more information, please visit www.gougra.ch.