A power station that uses the energy of flowing water during high or low tide to drive a turbine and generate electricity. It may be a barrage tidal plant or a tidal stream generator. A barrage tidal plant takes the form of a dam across a bay. At high tide, the gates in the barrage are open and water flows into the bay. Then they are closed and at ebb tide, the water is discharged from the bay through turbines. A tidal stream generator is an underwater turbine located where there is a strong tidal current.