Yes, this is a picture of a dump truck being hoisted up a mountain on cables. And no, it’s not photoshopped. You’re looking at the largest cable lift in the world, almost 2 kilometers long and 600 meters high, with two towers, a load capacity of up to 40 tons, cables 90 mm thick, and a pretty good speed of 5 meters per second.
The system took three years to build. And transport dumpers are not the heaviest loads it can carry, although they’re probably the most photogenic. The system can also lift whole ship containers.
Next surprise: this mammoth cable system is only a temporary fixture. It’s there to support construction of a huge $1.5 billion hydroelectric pumped-storage power plant called Linthal 2015.
Workers from the Linth-Limmern AG utility, its partners the Canton of Glarus and Axpo AG, are now building this electric Godzilla about an hour from Zurich, Switzerland, high in the rocky Glarner mountains of the eastern Alps. As you can see from the photo, the area is so mountainous that road access for construction is impossible—thus the cableways.
Peak energy demand in the European grid is growing steadily. Consumption patterns and forms of production have changed considerably since construction of the original infrastructure. Production peaks/shortfalls from renewable power sources may require balancing at short notice. Also, security of supply has become a higher priority. These considerations all increase the usefulness of electric generators with peak-power storage. As well as providing power, Linthal 2015 will basically act as a huge battery.
Workers expect to complete the plant next year. (Their grandparents had a little practice with this type of project, having built an artificial lake [the Limmernsee] and an earlier 480 MW power plant lower down the mountain, at 1,900m above sea level, in the 1960s.) The new storage lake (Muttsee) will be 600 meters higher up the mountain than the Limmernsee. The lakes will be connected via two headrace tunnels and produce a net hydraulic head of 623 meters (2,044 ft).
A huge, deep cave with an inclined underground access gallery will house all the turbine and transformer machinery. Planned pump and turbine power is about 1,000 MW. With the output from the original facility, the Linthal 2015 project will produce easily as much power as a nuclear generating station. It will rank among the top 15 pumped-storage plants in the world.
The cablecar system will be dismantled when a funicular railway inside the gallery is complete. The railway will transport large, heavy machine components—including 215-ton transformers—and personnel directly from the base installation site of Tierfehd, near the foot of the mountain, to the turbine cavern. 380 kV cables run along the gallery shoulders will transmit the generated power.
Now, would you like to hear about the avalanche protection system? OK, maybe next time…. (If you really want to know, access the article by Thomas Rentsch and Ruedi Stüssi in the online Proceedings of the International Snow Science Workshop 2009.)