Gerlos power plant lies at the south end of the village of Rohrberg on the escarpment of the Rohrerberg and is accessed by road from the north.
The power plant comprises the power house with adjoining tailrace reservoir, the switching station with an upstream 110-kV outdoor switching unit as well as auxiliary buildings that accommodate workshops, switching units and garages. Substation Zell am Ziller is located directly to the south of the power plant's outdoor switching unit. The new buildings of the power plant "Gerlos II" are situated to the north.
The buildings were erected within a rectangular ground plan and are characterised by hipped roofs and smooth exterior surfaces. The power house and the switching station buildings lie parallel in a roughly north-south direction and are connected by an archway with a passageway on top. The entrance to the machine hall is located on the west side and takes the form of an arched gate. The 44-metre long, 12-metre wide and 13-metre high hall receives light through four narrow high rectangular windows that are divided with steel glazing bars. The windows are placed in the axis of the four main machine sets. Each of the windows have two small high rectangular ventilation panels.
Small square window openings are arranged above the crane track. The cylinder-shaped enclosures of the generators, the peaks of which almost reach the crane track, dominate the interior of the machine hall. The crane track rests on the consoles of the reinforced concrete pillars which, in turn, accommodate supports for the ribbed ceiling. Two rows of lighting fixtures are arranged on the roof.
The longitudinal side of the machine hall is located upstream beside the forecourt of a ground level building that accommodates a 10-kV switching unit. Buildings with garages and a 25-kV switching unit are attached to the south side of the power house. The connecting passageway and the switching station receive light through small-sized windows. The entrance to the switching station takes the form of an arched gateway. Office space and two cells with transformers are accommodated on the ground floor. The control center, from which the 110-kV and 25-kV units are operated, is located on the top floor. A visual check of the outdoor switching unit can be carried out from a balcony located to the south. A two-storey building was built onto the west side of the switching station in a later construction phase.
A cableway on the mountain side runs from the workshop buildings to the Hochried surge tank.
Transportation of works water
After processing, the water is diverted to the Gerlosbach via a concrete tailrace channel.
The new building for "Gerlos II" to the north of Gerlos power plant is set at a right angle to Gerlos power house on the site of the old works entrance. The new power house comprises three square, flat roofed buildings the western frontal sides of which are adjacent to the entrance to the old power house.
The building was erected on a 36.5 x 43-metre site and is over 32 metres high. The height of the central cuboid above the downstream platform is approximately 23 metres. The building, which accommodates the machine hall, dominates the two side wings and is finished with anthracite concrete slabs. A large square window opening divided with steel glazed bars is located in the left lower section of the western frontal wall above two narrow horizontal rectangular windows and provides light for the high open space above the forecourt leading to the machine hall. The window also lies in the axis of the machine unit and faces the opening of the turbine outlet to the tailrace reservoir. The lower side wings are finished with grey external wall insulation and trellises. A narrow, high rectangular opening, which starts at the entrance level and extends into the upper floor, divides the front facade of the northern side wing, while the facade of the southern side wing in front of the transformer room has a square opening. Horizontal rectangular window openings on the longitudinal sides of the wings provide light for the interior. In some places, the trellises for ivy and vines extend over the window openings.
The new power house is accessed via a ramp to the north. The entrance gate leads to the forecourt with a high open space in front of the machine hall. The transformer room is accessed via a double-leaf gate in the southern side wing. The ball valves, machine unit and auxiliary rooms are located in the basement, ground floor and first floor. The protruding section over the side wing accommodates the 30-metre long, 13.50-metre wide and 8.30-metre high machine hall. The crane track, which protrudes into the room in the form of a console, runs under the horizontal rectangular windows along both longitudinal sides. A further horizontal rectangular window is situated on the eastern front side. The acoustic panels between the fairfaced ribs on the underside of the ceiling are finished in white, the walls of the machine hall are concrete grey and the floor has a black-white speckled finish. Both side wings have a two-armed staircase, a control room, ventilation rooms and other technical facilities. All of the architectural surfaces and components of the technical facilities are finished in line with the colour concept of the architects.
The ground level building for the machine workshops is located to the south of the new power house and covered with a saddle roof. It was erected on the site of the old workshop building and connects the new and the old building. Its smooth external surfaces are rendered, finished in yellow and feature high rectangular window openings and two entrances to the west.
A northwestern-oriented space, which is joined by the new tailrace reservoir, is formed between the new power house, the old power house and the switching station.
Works water supply
The works water from the Gmünd reservoir is supplied to the power house via a 90-metre pressure pipe which is connected to the existing works water channel.
Transportation of works water
After processing, the water flows into the tailrace reservoir with a net storage of approximately 25,000 m³ and a maximum storage level of 574 metres above sea level. A discharge reservoir near the Gerlosbach regulates the flow of water from the tailrace reservoir into the Gerlosbach.