A tidal barrage is a type of tidal energy system that captures the energy from the rise and fall of tides. The name "tidal barrage" is derived from its structure and functionality:
1. Tidal: This refers to the natural rise and fall of sea levels caused mainly by the gravitational pull of the moon (and to a lesser extent, the sun) on Earth's waters. The tide is the phenomenon this system aims to exploit for energy production.
2. Barrage: A barrage is a dam or barrier that spans a water body, usually an estuary. In the context of tidal energy, the barrage has sluice gates and turbines. As the tide rises, water flows into the estuary, and the sluice gates are closed, trapping water at high tide level. When the tide falls, a significant height difference (or "head") is created between the trapped water and the sea. This differential head is then used to drive water through turbines, generating electricity.
Hence, the name "tidal barrage" refers to a barrier system built across the entrance of an estuary to harness tidal energy. The barrage controls the flow of water, allowing for the generation of power as the tide rises and falls.