Enlarging Lake Grimsel

More water already flows into Lake Grimsel than it can hold - this being mainly in the summer months. By increasing the level of the existing dams by 23m more than 75% more water can be stored which allows the water to be better utilised throughout the year.

Most Important Building Stages:

• Overhaul of Spittallamm Dam
• Elevation of the Spittallamm and Seeuferegg dams by 23 m
• Rerouting of the Grimsel pass road, construction of a cable-stayed bridge

Benefits:

• More efficient use of the very large inflows, seasonal balancing
• Energy reserves for longer periods of limited electricity supply
• Contribution to flood control along the Aare
• Long-term with accentuated climatic changes: back-up in long periods of dry weather

Facts & Figures:

• Increasing the storage capacity from 95 to 170 million m3
• Energy capacity of the extra storage volume: 240 GWh;
• the larger lake: 510 GWh
• Investitment: CHF 260 million CHF (Stand 2006, +/- 20 %)
• (80 million CHF for the overhaul of the Spittallamm dam)
• Construction duration: approx.  6 years