The power station hall, also known as the machinery hall, is the largest area in a power plant. The facility in Alta was designed by the architect Egil Sorteberg, who has been the responsible architect for several power plants built by Statkraft. These kinds of halls must have a large, overhead travelling crane, which can move throughout the length/width of the hall. This crane manoeuvres the large elements in the turbine and generator. In the Alta Hall large longitudinal concrete girders support the crane. The walls are partly formed by the natural rock and partially laid with LECA (Lightweight Expanded Concrete Aggregate) blocks with large open gaps, which aids in absorbing sound. Sound-absorbing walls are a characteristic feature of power plants designed by Sorteberg. Since the Alta Power Plant is a facility that is open to visitors, extra resources were used in the construction of the power station hall. There are two turbines equipped generators. The tops of the generators are visually exposed inside the machinery hall.