Nant De Drance Hydropower Plant

Nant de Drance Hydropower Plant: Visiting Hours, Tickets, and Comprehensive Guide – Finhaut, Switzerland

Date: 04/07/2025

Introduction

The Nant de Drance Hydropower Plant, tucked deep within the Swiss Alps near Finhaut in the Valais region, stands as a monumental symbol of Switzerland’s commitment to renewable energy and innovative alpine engineering. As one of Europe’s largest pumped-storage facilities, it plays a vital role in stabilizing the national grid, supporting the integration of wind and solar power, and ensuring a reliable energy future. With its impressive 900 MW capacity and cutting-edge, low-impact underground design, Nant de Drance exemplifies the fusion of sustainability, technology, and environmental responsibility (Nant de Drance SA; AFRY; Power Technology; Finhaut Municipality).

This guide delivers in-depth information on the plant’s history, technical marvels, visiting options, ticketing, accessibility, and practical travel advice for exploring both Nant de Drance and the broader Valais region.

Overview & Significance
Historical Background & Construction
Technical & Engineering Highlights
Environmental & Societal Impact
Visitor Information: Hours, Tickets & Tours
Travel Tips & Nearby Attractions
Frequently Asked Questions (FAQ)
Essential Facts & Figures
References & Further Reading

Overview & Significance

Nant de Drance is a cornerstone of Switzerland’s energy strategy. It enables large-scale energy storage and helps balance the grid as intermittent renewables rise, by rapidly switching from pumping to generation within five minutes. Its location—between the Vieux Emosson (upper) and Emosson (lower) reservoirs—uses the natural elevation to efficiently store and generate power, while its entirely underground design minimizes environmental and visual impact.

Historical Background & Construction

Vision and Planning

The project was initiated in the early 2000s to address Switzerland’s growing need for flexible, large-scale energy storage. In 2002, AFRY (then Pöyry) conducted early feasibility studies, leading to approval by the Swiss federal authorities in 2007 and the formation of Nant de Drance SA in 2008. Ownership is shared among Alpiq Suisse SA, Swiss Federal Railways, Industrielle Werke Basel, and Canton of Valais (Nant de Drance SA).

Major Construction Phases

2008–2011: Excavation of 1.7 million m³ of rock, creation of 18 km of tunnels, and the main access tunnel (5.6 km) using a TBM with a 9.45 m diameter (Sika; AFRY).
2011–2014: Construction of the underground machine hall (194 × 52 × 32 m) and transformer cavern, and raising of the Vieux Emosson dam wall by 20 m to double storage capacity (Sika).
2014–2020: Installation of six 157 MW reversible Francis pump-turbine units and two 425 m deep vertical shafts for high flexibility (Power Technology; AFRY).
2020–2022: Extensive testing, culminating in official commissioning in July 2022 and inauguration in September 2022 (Nant de Drance SA).

Technical & Engineering Highlights

Underground Design: Entirely subterranean, the plant’s construction minimizes visual and ecological disturbance, using recycled excavated material for concrete (Sika).
Reservoir System: Utilizes the Emosson and Vieux Emosson reservoirs (up to 395 m hydraulic head), with the upper dam expanded to 25 million m³, supporting a total hydro reservoir capacity of 227 million m³ (Power Technology).
Power & Flexibility: 900 MW installed capacity, 2.5 billion kWh annual production, and capability to shift between pumping and generating in under five minutes (Hydropower.org).

Environmental & Societal Impact

Environmental Stewardship

Minimal Footprint: Underground placement preserves the alpine landscape (Powertage).
Reservoir Expansion: By increasing the size of an existing reservoir rather than building a new one, further ecosystem disruption was avoided.
Compensation Projects: Fourteen habitat restoration and biodiversity initiatives, including alpine meadows restoration, reforestation, wildlife corridors, and aquatic ecosystem management (Nant de Drance).
Efficiency: Over 80% energy storage yield, supporting decarbonization of the Swiss and European grids.

Societal Benefits

Grid Stability: Key asset for energy security as renewables grow (Nant de Drance).
Economic Boost: CHF 2 billion investment, thousands of jobs during construction, and ongoing skilled employment (Powertage).
Regional Development: Enhances Valais’s reputation for innovation and attracts tourism and research.

Visitor Information: Hours, Tickets & Tours

Visiting Hours

Season: Guided tours typically run from June to September, with occasional spring and autumn dates.
Times: Most tours start between 9:00 AM and 3:00 PM. Always confirm current schedules on the official website.

Tickets & Booking

Prices: Adult tickets usually CHF 25–35; discounts for children, students, and seniors.
Advance Booking: Mandatory due to safety and capacity limits. Book via the official website or phone.
Group Tours: Free for groups of 10+ (by arrangement); special requests for smaller groups may be considered (Alpiq).

Guided Tours

Languages: French, German, and English.
Duration: 2–3 hours, including a descent 600 m underground to the machine hall and interactive exhibits.
Age Limit: Minimum age generally 12 years for safety reasons.
Group Size: 10–20 people per tour.

Accessibility

Mobility: Underground areas are not fully accessible; inquire about accommodations in advance.
Facilities: Visitor center at Emosson Dam offers educational exhibits, café, restrooms, and restaurant.

Safety Guidelines

Clothing: Warm layers and sturdy shoes recommended (underground temperature ~12°C).
Safety Gear: Helmets and vests provided and required.
Photography: Permitted in designated areas only.

Travel Tips & Nearby Attractions

Getting There

By Car: Accessible via mountain roads from Martigny (Switzerland) or Chamonix (France), with parking by Emosson Dam.
Public Transport: The Mont-Blanc Express train connects Martigny and Chamonix, stopping at Finhaut. Shuttle or taxi connects Finhaut to Emosson Dam (Finhaut Municipality).
Hiking: Scenic trails link Finhaut, Emosson Dam, and area viewpoints.

Local Highlights

Emosson Dam: Panoramic views, walking trails, and a miniature railway.
Finhaut Village: Traditional alpine atmosphere and access to nature.
Alpine Hiking: Numerous routes for all skill levels.
Mont Blanc & Trient Valley: Ideal for combining technical tours with natural and cultural excursions.

Tips

Plan Ahead: Tours must be reserved in advance.
Combine Activities: Pair your plant visit with local hikes or cultural stops.
Seasonal Events: Check for local festivals or educational workshops.

Frequently Asked Questions (FAQ)

Q: How do I book a tour?
A: Reserve in advance via the official Nant de Drance website or by phone.

Q: Are children allowed?
A: The minimum age is typically 12 years.

Q: Is the plant accessible for those with reduced mobility?
A: Underground areas are not fully accessible; contact the visitor center for options.

Q: What should I bring?
A: Warm clothing, sturdy shoes, and a camera for scenic views.

Q: Are there group discounts?
A: Group tours (10+) are often free; individual ticket discounts available for students, seniors, and children.

Q: Can I visit alone or in a small group?
A: Standard tours are for groups of 10+, but contact the visitor center for special arrangements.

Q: What else can I see nearby?
A: Explore the Emosson Dam, Finhaut village, hiking trails, and the scenic Valais region.

Essential Facts & Figures

Installed Capacity: 900 MW (comparable to a large nuclear power plant)
Energy Storage: 20 GWh (equal to 400,000 electric car batteries)
Switching Time: <5 minutes from pumping to generating
Infrastructure: 18 km of tunnels, machine hall 600 m underground
Altitude: Vieux Emosson reservoir at 2,225 meters

Contact & Further Information

Official Website: www.nant-de-drance.ch
Phone: +41 27 720 47 30
Email: [email protected]
Address: Nant de Drance SA, Rue des Creusets 41, 1950 Sion, Switzerland

Summary & Conclusion

Nant de Drance is a beacon of sustainable energy and alpine engineering, combining a massive underground pumped-storage system with ecological mindfulness and regional cultural heritage. Guided tours offer rare access to this facility, while the Valais region’s natural and cultural attractions provide a complete visitor experience. Book your visit in advance, dress for alpine conditions, and explore both the technical wonders and scenic beauty that define this corner of Switzerland.

For more details on planning your visit, explore the official plant website, Alpiq visitor information, and the Finhaut tourism office.

Plan your journey and witness the power of the Alps firsthand!