Erected in 1924 as one of the first storage power stations in Bavaria, the plant exploits the 200-metre difference in height between the two lakes, Walchensee and Kochelsee, to generate electricity. A new information centre has been constructed for the up to 100,000 visitors who come here every year. To integrate the centre into the existing context, the structure was built into the slope of the site, with planted flat roofs that merge with the surroundings. All that is visible is a curved transparent roof that seems to hover above the ground. This lightweight triangular membrane structure is drawn over the forecourt to the exhibition and restaurant facilities, which are housed in two flanking tracts. The V-shaped entrance courtyard opens on the third side to the existing buildings. The roof consists of a single-layer ETFE membrane, through which visitors have a view of the mountains. With an area of 390 m2, the membrane weighs only 180 kg. The lightweight form of construction was, however, designed to bear great snow loads (up to 165kg/m2). The load-bearing structure consists of a series of prefabricated laminated-timber compression arches with a maximum span of 27m. The compression loads from the arches are transmitted to the solid concrete slabs over the flanking buildings and from there to the ground. The membrane is stretched over a secondary structure of aluminium tubes laid over the timber arch members at 1.25m centres. Since the roof covers an open courtyard space, it must also be capable of resisting strong suction forces. Instead of securing the membrane from the top with screws or bolts, which could damage the watertight seal, it was fixed by welding plastic strips to the underside and clamping these into the secondary tubular sections.