According to a study by the university of Liverpool 15% could be generated using estuary barrages and turbines and 5% using tidal currents in the open sea, together 20%. This form of energy would be more reliable than wind. Disadvantage are high operational cost as the agressive salt water has negative impact on the turbines, increasing maintenance cost. The largest potential for the UK (and the world) would have a Severn Barrage (8.6 GW). Required would be a 16 km dam in the Severn on the border of England and South-Wales, bringing the total cost at 34 billion GBP. The study pleads for starting smaller projects first and gain experience before larger projects could be tackled.
[bbc.co.uk] – UK tidal power has huge potential, say scientists
[royalsocietypublishing.org] – Appraising the extractable tidal energy resource of the UK’s western coastal waters
[spiegel.de] – Gezeitenkraftwerke könnten 20 Prozent des Stroms liefern
[guardian.co.uk] – Abandoned Severn tidal power project to be reconsidered
[google.maps] – Rance Tidal Power Station
[wikipedia] – Rance Tidal Power Station