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Increased controllable power production in winter

Additional flexible, controllable power production in winter is required to strengthen the security of supply in Switzerland. The participants of a federal “Hydropower Round Table” have agreed on 15 projects that promise around 2000 million kilowatt-hours (kWh) of additional electricity in the winter months by 2040 – enough to supply around 1.8 million Swiss households with renewable electricity for three months. Alpiq is committed to implementing projects as quickly as possible together with its partners.

In future, will there be enough electricity in wintertime and at economically viable prices in Switzerland? This is the question that politics, business and society are asking with increasing frequency. The reasons for this are well known: the lack of an electricity accord with the EU increases the risk of an electricity shortfall in Switzerland, because from 2025, it will be more difficult to close the wintertime electricity gap with imports from surrounding countries. This is important, because Switzerland has traditionally been a net electricity importer during the winter half-year. The prices on the European electricity exchanges for this winter underline how important and scarce this winter energy is. 

That’s why various solutions and approaches are currently being discussed in Switzerland, under time pressure and at various levels, on how to strengthen the security of supply in winter. The federal government, the cantons, the federal Electricity Commission (ElCom) and industry associations such as the VSE (text in German) are considering a variety of approaches, some of which include the selective use of gas-fired power plants. All the key players agree on one point: Switzerland needs more flexible, controllable power production in winter. Hydropower – the backbone of the Swiss electricity supply for decades, and the most important domestic renewable energy source – is predestined for this.

Hydropower Round Table: List of 15 projects

Experts have been exchanging views on this topic since August 2020 at the invitation of Federal Councillor Simonetta Sommaruga, Head of the Federal Department for the Environment, Transport, Energy and Communication (DETEC). This so-called “Hydropower Round Table” has identified 15 projects (text in German) that can make a major contribution to security of supply – and at the same time have a comparatively low impact on biodiversity and the landscape for each additional gigawatt-hour (GWh) in storage capacity. They also likely meet the current legal requirements. If all of these 15 projects were implemented, they would achieve seasonal storage production of around 2000 GWh (i.e., 2000 million kWh) by 2040. This corresponds to the electricity consumption of around 1.8 million households over three months.

The high-potential “Gornerli” project

With an additional 650 million kWh of wintertime production, i.e. around a third of the identified potential, the “Gornerli” multi-purpose reservoir above Zermatt clearly has the greatest potential on the “Hydropower Round Table” list. The joint project between the power plant company Grande Dixence SA (shareholders Alpiq, Axpo, BKW, IWB) and the municipality of Zermatt would enable the storage of around 150 million additional cubic metres of water for the winter, which would be turbined in the Grande Dixence power plant complex. At the same time, the storage project would act as a flood retention basin, providing a very valuable optimisation for the protection of Zermatt and positive effects for the Mattertal valley as a whole.

Another promising project is in the Oberaletsch region. This project would make use of a lake that is currently forming there naturally from melting glaciers (content 25 million cubic metres by 2030). This would enable the production of around 100 million kWh of additional electricity from renewable sources; around 50 million kWh of this would be winter electricity. Electra-Massa AG is the project developer (shareholders: Alpiq, BKW, IWB, Axpo, FMV and Groupe E). The project would be implemented in partnership with the concession communities of Naters, Riederalp and Bitsch, as well as with the canton of Valais. 

Numerous projects to raise existing dams

The Hydropower Round Table list also includes several projects to raise existing dams. These have the advantage that they enable additional storage, and at the same time have a comparatively low impact on the environment. However, this means that less additional water can be stored for the winter months than would be the case with a new reservoir. From a technical point of view, dams can be raised from five to a maximum of 10 metres in many places. One example is the raising of the dam of Electricité d’Emosson (shareholders: Alpiq, EDF), which would increase the storage capacity of Switzerland's second largest reservoir by 58 to 115 million kWh for the winter. Forces Motrices de la Gougra SA (shareholders: Alpiq, Rhonewerke, Oiken and the concession communities Anniviers, Chippis, Chalais and Siders) could generate up to 120 million kWh of additional wintertime electricity, either by raising the Moiry dam and/or replacing the Turtmann dam.

How can the Hydropower Round Table projects be implemented? The inclusion of the projects on the list underscores their potential. But that alone is not enough: time is ticking, and there’s still a long way to go. The framework conditions set by federal-level politics in the design of the «Mantelerlass» (Energy Act and Electricity Supply Act) is of key importance. Furthermore, good coordination is required between the key players in the electricity sector and the authorities, as well as a willingness by all sides to compromise when balancing the interests of electricity security of supply with nature and landscape protection.

“We must not waste any time; we have to implement good projects quickly. The “Gornerli” project, for example, is ideal. There is hardly a more favourable location in Switzerland to produce so much additional, controllable winter electricity. No new installations would have to be constructed – i.e. no penstock, no control centre, no new electricity pylons – except for a comparatively low dam and a pumping station. From a winter supply perspective, this project is a must.”


Amédée Murisier
Head of Hydropower Production Switzerland