Environmental implications of tidal power generation

Suitable sites for tidal power generation are mostly situated in estuaries, where with a high tidal range of 5-15 m, the construction of a barrage is proposed to impound water during tidal rise. Electricity is then generated using turbines exploiting the difference in level as the tide drops outside the impounded area. The most important factor with respect to water quality change is the reduced tidal currents, following impoundment, acting with the additional retention time of water in the system to compound pollution problems. Further environmental effects can include matters concerned with coast protection, flood control and groundwater. The creation of a large impounded area can lead to pressure for its development as a water-based leisure facility. The author discusses all the above issues and, despite the clear fact that all the matters involved are clearly site-specific, some overall conclusions are drawn concerning the environmental effects of tidal power generation in relation to alternative methods of electricity generation.