The basic equipment of every storage power plant is a storage lake or reservoir. In the alpine mountain range, i.e. in the valleys in front of a water-retaining structure, storage lakes are formed through the accumulation of glacier and precipitation waters. In lower regions, the reservoirs are usually fed by a canal from a nearby river. Via pressure shafts, the stored water precipitates into the depth at a speed of more than 100 km/h and subsequently drives the turbines located in a lower level power house. The generator converts the rotary motion thus created in electricity.