How do tidal power plants generate electricity? A barrage allows water to flow during high and low tide, this turn's the plant's turbines. A barrage holds back water during high tide. The force of the water against the barrage turns the plant's turbines. A barrage store water during high and low tide. When the water is released, it turns the plant's turbines. A barrage stops water from flowing out at low tide, creating a force that turns the plant's turbines.