Construction of the new Muttsee Dam: A Key Component of Pumped Hydro Energy Storage in Switzerland
Boosting renewable energy capacity through the design and construction of Switzerland's largest underground pumped storage facility.
The Muttsee Dam is a critical component of the Linthal 2015 Project, a significant pumped-storage hydropower plant that will boost Switzerland’s renewable energy capacity. This project features a 1,000 MW pumped hydro energy storage system, connecting the Limmern Reservoir (lower storage) with the newly expanded Muttsee Reservoir (upper storage) via underground infrastructure, including the headrace penstock, powerhouse, and tailrace tunnel.
The Muttsee Dam, located in the Glarus Alps, retains the upper reservoir for the Linthal 2015 project. Built from 68 concrete blocks, the 1,050-meter-long gravity wall will be one of the longest of its kind in Europe. The dam’s construction will triple the capacity of the Muttsee reservoir, bringing its storage volume to 25 million cubic meters. The dam, standing 36 meters high, was designed with a V-shaped layout to preserve protected wetland areas by positioning it along the southern border of the natural lake.
Gruner, acting as part of an engineering consortium, was appointed to design this exceptional structure and oversee the on-site works. The total concrete volume for the dam is 250,000 cubic meters. To ensure the watertightness of the rock foundation, a grout curtain was constructed, and jet grouting was used to stabilize the scree slope on the left bank, preventing water loss.
Additional key features include an uncontrolled surface spillway with a stilling basin, a bottom outlet with a valve chamber, a grouting and inspection gallery, and a permanent access tunnel. The logistics for the construction site, located at an altitude of nearly 2,500 meters, required a sophisticated site installation concept using aerial cable cars, as no access road was available.
Gruner’s Role and Services:
- Final design of the dam and appurtenant structures
- Preparation of tender documents and tender evaluation
- Construction drawings and supervision of on-site works during all project phases, including tender design, procurement assistance, and detailed design
The Muttsee Dam plays a vital role in supporting pumped hydro energy storage as part of Switzerland's renewable energy strategy. By connecting the Limmern and Muttsee reservoirs, the Linthal 2015 Project ensures reliable energy storage and distribution, enhancing grid stability during peak demand.
Related Project: Linth-Limmern Power Plant
Gruner was also involved in the Linth-Limmern Power Plant, where we applied our fire safety engineering expertise. To learn more about this related project, visit Linth-Limmern Power Plant.
Services
- Hydropower & dam engineering