Following the demise of the mining industry in 1930, water from the Upper Harz Water Regale was switched to generating electricity, some new structures being built as a result. The generation of electricity was carried out by Preussag until 1980 in the Kaiser Wilhelm (maximum output 4.5 MW) and Ottiliae (maximum output 1.5 MW) mines. These hydropower stations were closed in the early 1980s when water rights had expired and the profitability of power stations steadily declined against a background of sharply increasing wages and stagnating energy prices. Nevertheless, in Sankt Andreasberg the water of the Oderteich, transferred along the Rehberg Ditch, is still used to generate electricity today. In addition to the Teichtal and Grundstraße power stations, there are two stations in the Samson Pit: the Grüner Hirsch power station at a depth of 130 metres and the Sieberstollen power station at 190 metres.