In the most western part of Austria, called Vorarlberg, lies the hydropower plant Kops I. As the energy demand is steadily increasing, the owner of the plant, the Vorarlberger Illwerke AG, decided to improve the energy efficiency of the plant by adding the pumped hydropower storage plant Kops II.
The plant is almost totally constructed inside the mountains in order to preserve the natural beauty of the Montafon Valley. It has a 5.5 kilometre pressure tunnel, 1.1 kilometre pressure shaft, 140 metre surge shaft, and a new powerhouse located inside a cavern. As a result, the environmental impact assessment for the new power plant was approved by the environmental authorities in a very short time.
The new plant adds about 600 GWhs to the already produced capacity of 430 GWh of Kops I without any additional water consumption. Pöyry provided the site supervision services for the project.