Nant de Drance
Nant de Drance pumped hydro overview.
Nant de Drance is an underground pumped-storage power station between the Emosson and Vieux Emosson reservoirs in Valais. Its six reversible pump-turbines store surplus electricity and provide flexible generation for the Swiss and European electricity systems.In OperationSwitzerland
At a Glance
Capacity
900 MWEnergy storage
20,000 MWhOperator
Data coming soonCountry
SwitzerlandLocation
46.066°, 6.901°Website
Official project pageOwnership
2 records| Share | Organisation | Role | Details | Period |
|---|---|---|---|---|
| Unknown | Operator | HYDRO Exploitation took over the plant operation and maintenance mandate on 1 January 2025. | From Jan 2025 | |
| Unknown |  | Owner | Project company responsible for the Nant de Drance pumped-storage installation. | Current / not dated |
Organisations
21 recordsOrganisations recorded as working on this asset or its project, and their role.
| Organisation | Role | Details |
|---|---|---|
| Design and project engineeringEngineering Consulting And Project Management | AFRY documents planning, design, permitting, procurement, construction management and commissioning support for the scheme over 2002–2022, including the legacy AF Consult and Pöyry teams. | |
| Dam inspection supportSurvey Inspection | The 2025 activity report identifies Alpiq participation in inspections of the dam and associated structures. | |
| Project company shareholderFinance Insurance Legal | 39% shareholder in Nant de Drance SA at 31 December 2025. | |
| Hydraulic steelwork supplierEquipment Supply | ANDRITZ HYDRO received the January 2011 hydraulic steelwork contract covering pressure-shaft linings, inlet valves and gates. | |
| Geological and hydrogeological engineeringResource Assessment And Surveys | Tissières provided geological studies and monitoring of underground excavation, including geological sections and hydrogeological observations. | |
| Shared reservoir operating agreement partnerOther | Électricité d’Émosson, SBB and Nant de Drance agreed operating arrangements for their installations sharing the Emosson reservoir. | |
| Project company shareholderFinance Insurance Legal | 10% shareholder in Nant de Drance SA at 31 December 2025. | |
| Hydroelectric machinery and warranty supportEquipment Supply | GE Hydro supplied the generating machinery; the 2025 activity report records GE machinery warranty work and GEPC frequency-converter engineering. | |
| Underground and civil works consortiumEpc Balance Of Plant | GMI undertook access and hydraulic tunnels, pressure shafts, caverns, concrete works and the Vieux Emosson dam heightening. | |
| Dam heightening and construction supervisionEngineering And Design | Gruner Stucky designed and supervised the Vieux Emosson dam heightening and provided additional plant and tunnel construction supervision from January 2014. | |
| Commissioning supervisionEngineering And Technical | HYDRO Exploitation supervised and monitored the commissioning programme, including functional, hydraulic, electrical and grid synchronisation tests. | |
| Operation and maintenance contractorOperations Maintenance | HYDRO Exploitation took over operation and maintenance on 1 January 2025, integrating the existing operating team. | |
| Civil works consortium commercial leadEpc Balance Of Plant | Implenia Bau AG, now Implenia Schweiz AG, was the commercial lead in the GMI civil works consortium. | |
| Project company shareholderFinance Insurance Legal | 15% shareholder in Nant de Drance SA at 31 December 2025. | |
| Civil works consortium technical leadEpc Balance Of Plant | Marti Tunnelbau AG, now Marti Tunnel AG, was the technical lead in the GMI civil works consortium. | |
| Pumped-storage project companyOwner Operator | Nant de Drance SA is responsible for the pumped-storage installation and appoints its operation and maintenance contractor. | |
| Former operation and maintenance contractorOperations Maintenance | SBB operated the plant from commissioning in 2022 until the mandate transferred to HYDRO Exploitation on 1 January 2025. | |
| Project company shareholderFinance Insurance Legal | 36% shareholder in Nant de Drance SA at 31 December 2025. | |
| Vieux Emosson reservoir partnerOther | SBB owns the Vieux Emosson dam and participated in agreements governing the shared reservoirs used by Nant de Drance. | |
| Transmission connection operatorGrid Connection | Swissgrid developed the transmission connection serving Nant de Drance; its network infrastructure is separate from the generating installation. | |
| Powerhouse cavern and structural engineeringEngineering And Design | The former BG engineering team, now WSP, designed the powerhouse cavern structures and coordinated their construction with GMI and GE Hydro. |
Supplier registration
Contact page onlyHow suppliers get onto this project's radar: its standing register, supplier portal or contact route.
Enquiries can be directed to the project company through its contact page. Suppliers can use this route to introduce relevant services.
The Nant de Drance contact page provides a project company enquiry route.
SourceChecked 29 Oct 2026