Nant de Drance, high-altitude pumped‑storage plant in the canton of Valais in Switzerland
Background
As power systems integrate more renewable generation, large-scale energy storage is becoming increasingly important. While battery technologies are advancing rapidly, hydropower technology still accounts for more than 90% of existing storage capacity: Water is pumped uphill when there is extra supply and turbinated down when there is demand is higher.
Switzerland benefits from natural conditions, namely mountains, that support this technology. One such asset is Nant de Drance, a high-altitude pumped‑storage plant in the canton of Valais, co-owned by Alpiq, one of Switzerland’s three system-critical utilities and a long-standing EIP partner and portfolio company.
Located at 2,000 metres above sea level, Nant de Drance came into operation in 2022 after more than a decade of planning and construction. The plant has over 900 megawatts of capacity and is key for stabilizing the electricity grid. At the same time, the infrastructure interacts within sensitive Alpine ecosystems, as well as downstream environments that are increasingly exposed to climate-related risks such as flooding.
Action
Already during construction, Nant de Drance defined 14 environmental measures to address or compensate potential impacts, in close collaboration with environmental organisations like WWF and Pro Natura, and public authorities.
In the immediate vicinity of the dams at the Emosson Lake, measures focus on ecological restoration. These include the rehabilitation of areas affected during construction, like the former construction site at Le Châtelard, with the objective of restoring local biotopes for amphibians, for example.
Beyond the immediate project area, measures extend regionally, combining biodiversity restoration with flood management. A key component is the restoration of the Trient river at Vernayaz, in the lower lands of the valley. The widening of a 300‑metre river section increased flood capacity and can stabilize the river during high flows, while also creating wetlands and ecological corridors. Nant de Drance covered these costs, CHF 3.6 million, from its operating budget.
These works form part of a broader flood protection programme for the municipalities of Vernayaz and Martigny that were defined following the 2023 floods.
Outcome
By combining site-level ecological restoration with regional flood protection measures, Nant de Drance’s environmental measures contribute to both biodiversity enhancement and increased resilience to natural hazards for local communities.
Note: Case study for illustration purposes only. Holdings are subject to change, this does not constitute investment advice to buy or sell the presented securities.
Tags
- Alpiq |
- Nant de Drance |
- Switzerland