Owner(s) Linth-Limmern AG Construction began 1957 | Upper reservoir Mutt/Limmern | |
Status Operational; under expansion Commission date 1964Tierfehd PS: 2009Limmern PS: 2015/2016 est. | ||
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 operationEdit
The main reservoir is Lake Limmern which was created by a 146 m (479 ft) tall and 375 m (1,230 ft) long arch dam on the Limmern Creek. It can store up to 92,000,000 m3 (74,586 acre·ft) of water which can all be used for power generation. The reservoir is at an elevation of 1,857 m (6,093 ft) while Lake Mutt, located above it, is situated at 2,474 m (8,117 ft) above sea level. Lake Mutt has a storage capacity of 9,000,000 m3 (7,296 acre·ft) which is currently being expanded to 25,000,000 m3 (20,268 acre·ft) 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 623 m (2,044 ft).
Lake Limmern also provides water for conventional hydroelectric and pumped-storage generation at the Tierfehd Power Station further down in the valley. This includes three 87 MW Pelton turbine-generators and one 140 MW pump-generator that is used for pumped-storage. Additionally, Lake Hintersand in an adjacent valley provides water to two 20 MW Pelton turbine-generators within the Tierfehd Power Station. Water used for power generation at Tierfehd is discharged into the Tierfehd Balancing Reservoir. The water in this reservoir can either be pumped back up to Lake Limmern or directed down to the Linthal Power Station's two 17.2 MW Pelton turbine-generators. From there, the Linthal Power Station discharges the water into the Linthal Balancing Reservoir and then into the River Linth. The Tierfehd Balancing Reservoir is located at an altitude of 811 m (2,661 ft) and has a storage capacity of 259,000 m3 (210 acre·ft) but is currently being expanded to 560,000 m3 (454 acre·ft). The Hintersand Reservoir has a storage capacity of 110,000 m3 (89 acre·ft) and is situated at 1,298 m (4,259 ft). Finally, the Linthal Balancing Reservoir is at the lowest altitude, 676 m (2,218 ft) and withholds 210,000 m3 (170 acre·ft) of water.
