NOVELTY - The plant has a set of turbine generator units (1) provided in a diversion tunnel (2) of a weir system. The turbine generator units are arranged individually or in groups beside or above each other in the diversion tunnel. The diversion tunnel is closed off by a set of gates (4). The gates are attached securely to a building structure, and include a set of devices (6) that allows the gates to be opened for flowing water. The diversion tunnel includes a set of openings on a headwater side, where the openings are provided with a trash rack (5).    USE - Plant for generating electric power from a flowing medium i.e. water, in a building structure.    ADVANTAGE - The plant allows the turbine generator units to be arranged individually or in groups beside or above each other in the diversion tunnel, so that a specific tunnel cross-section can be used as best possible to make use of the energy. The plant allows the diversion tunnel to be closed off by the gates, so that installation and repair work can be performed easily. The plant allows the gates to be attached securely to the building structure, thus guaranteeing a stable closure that can withstand a strong current. The plant allows the gate devices to be opened for flowing water, so that power generation can be controlled more effectively. The plant allows the diversion tunnel to be provided with the openings on the headwater side so as to provide better flow paths. The plant allows the openings to be provided with the trash rack to prevent contaminants from entering into turbines. The plant allows the openings to be provided with a cross-section that is large enough to lift the turbine generator unit out upwards, so that the turbine generator units can be installed and removed easily for maintenance purposes without a shutdown period.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view of a plant.    Turbine generator units (1)    Diversion tunnel (2)    Gates (4)    Trash rack (5)    Devices (6)