The invention relates to an device for production of energy from currents in water, comprising a first element (10), a second element (20) and a plurality of turbine modules (750) connected to the first element. The second element is mounted on the first element in an approximately perpendicular relationship, the first element is adapted for submersion below a water surface, and an upper part of the second element projects up above the water surface when the plant is in production. The invention also relates to an anchoring device for a floating plant (10, 20), comprising mooring lines (24a, 24b) which are connected at one of their respective ends to the plant and which are connected at their respective second ends to buoys (50, 52), where the mooring lines (24a, 24b) extend substantially horizontally between the plant and the respective buoys.