About Kopssee Dam

The Kops Reservoir in the Montafon valley of Vorarlberg sits at 1,809 metres above sea level among some of the highest peaks in western Austria. The 122-metre arch dam, completed in 1969, stores 43 million cubic metres from the upper Ill catchment and is part of Illwerke vkw's extensive Vorarlberg pumped-storage network. The Kops II expansion, completed in 2008, added a new powerhouse and pump turbines that significantly increased the system's flexibility for grid balancing. Together, the original Kops facility and Kops II can respond to changes in electricity demand within minutes, making the Kopssee system a key contributor to European grid stability. The surrounding Silvretta Alps offer world-class ski terrain in winter and glacier trekking routes in summer. The reservoir has a distinctive emerald colour from glacial flour suspended in the meltwater, and its surface frequently freezes over from December through April, requiring ice management procedures before the spring inflow season.