Linth–Limmern Power Stations

Geschichte

The Linth–Limmern Power Stations are a system of hydroelectric power stations located south of Linthal in the canton of Glarus, Switzerland. Using five reservoirs and three power stations at steep variations in altitude, the scheme currently has an installed capacity of 479.8 MW. Construction on the Limmern Dam and Linth–Limmern Power Stations began in 1957. The Limmern Dam was complete in 1963 and the power stations were all operational by 1968. By 2009, the 140 MW pumped-storage component between Lake Limmern and Tierfehd was commissioned. In 2010 construction began on the Linthal 2015 project, which is the addition of a 1,000 MW pumped-storage component between Lake Mutt and Lake Limmern. This also includes an expansion of Lake Mutt and the Tierfehd Balancing Reservoir.Design and operationThe main reservoir is Lake Limmern which was created by a 146m tall and 375m long arch dam on the Limmern Creek. It can store up to 92000000m3 of water which can all be used for power generation. The reservoir is at an elevation of 1857m while Lake Mutt, located above it, is situated at 2474m above sea level. Lake Mutt has a storage capacity of 9000000m3 which is currently being expanded to 25000000m3 for the new pumped-storage power station. Between Lake Mutt and Limmern is a 4.4 MW power station containing a single Pelton turbine-generator. Between these two lakes is also the site of the current expansion. With the storage capacity of Lake Mutt being increased, a new power station with four 250 MW Francis pump-turbine-generators is being constructed. This will allow water to be shifted between both lakes in order to produce pumped-storage hydroelectricity. During periods of low demand, water can be pumped from Lake Limmern to Lake Mutt and when energy demand is high, the water is released down to the power station for generation. The same turbines that pump the water to Lake Mutt reverse into generator mode. The difference in elevation between the two lakes affords a net hydraulic head of 623m.