Swiss pumped storage operator Nant de Drance SA reported increased operating hours and energy throughput in 2025, underscoring its expanding role in stabilising the grid and supporting renewable integration, while advancing environmental commitments and completing a leadership transition.
Switzerland’s flagship pumped storage hydropower facility, Nant de Drance SA, delivered a strong operational performance in 2025, underlining its growing role in supporting grid stability and renewable energy integration.
The plant increased its operating hours by 8% compared to 2024, running on average 19 hours per day with at least one unit in pumping or generating mode. Total electricity production reached 1,046GWh (2024: 974GWh), while energy consumed for pumping rose to 1,284GWh (2024: 1,176GWh).
The six pump-turbine units accumulated more than 20,600 operating hours over the year. According to company chairman Michaël Plaschy, the results reflect “a high level of technical expertise” and confirm the facility’s “essential contribution to grid stability and security of supply,” particularly in balancing intermittent solar and wind generation.
The total energy produced in 2025 is equivalent to around 52 full refills of the upper reservoir at Vieux Emosson, highlighting the scale of the plant’s storage and flexibility capabilities.
Operating costs for 2025 amounted to CHF 97.7m (US$124m) and were fully covered by shareholders, in line with the company’s partner-based structure. Equity accounted for 25.19% of the balance sheet.
Under this model, shareholders are entitled to production and pumping capacity in proportion to their shareholdings and, in return, assume responsibility for covering annual costs including maintenance, depreciation, water fees and financing charges. As a result, the company’s published financial results do not reflect its economic performance directly; instead, the value of the plant’s flexibility is realised by shareholders on electricity markets.
A change in leadership took place at the start of 2026. After 13 years with the company, including serving as CEO since January 2021, Alain Sauthier stepped down at the end of 2025 to pursue new opportunities.
He was succeeded by Jeremy Urech on 1 January 2026. Chairman Plaschy praised Sauthier’s “exemplary commitment” and key role in both the construction and commissioning phases of the project, while welcoming Urech and wishing him success in his new role.
The company also reported continued progress on environmental mitigation measures linked to the plant’s construction. Two additional projects were completed in 2025: the widening of the Trient River at Vernayaz and the redevelopment of the Châtelard valley. To date, 10 of the 14 planned compensation measures have been implemented.
Since 2022, Nant de Drance SA has published an annual sustainability report as part of its management report, reflecting its commitment to transparent communication with stakeholders.
The company’s 2025 annual report is scheduled for publication on 30 April 2026 and will be submitted for approval at the Annual General Meeting on 8 June 2026.
No further changes are planned to the Board of Directors. However, Nicolas Ecoffey and Reto Müller joined the board in December 2025 as representatives of Swiss Federal Railways, replacing outgoing members Joëlle Hars and Sibylle Wälchli.
