21st century tidal power technology has already reached an advanced stage of development. Whilst the utilisation of tidal power in the 20th century was limited to a range of tidal barrage installations, the major new developments reaching the deployed prototype stage are focused on harnessing the tidal currents rushing through natural marine pinch points. These tidal stream systems presently under trial, fall into two types; those that use something that is akin to a marinised wind turbine and those that use hydraulic pumps to generate power from leverage created by water rushing over hydrofoils.

Impression of an underwater tidal stream energy farm
Copyright: The Engineering Business Ltd.