Tidal energy

One of the first tidal power stations was La Rance, south of St Malo in Brittany, France. Completed in 1966, and still generating, it has an installed capacity of 240 MW exploiting a tidal range of up to 8m at the entrance to the estuary.

Whilst short of the world’s greatest tidal range (11m in the Bay of Fundy between Nova Scotia and New Brunswick), the entrance to the English Channel acts as an Atlantic funnel and places a number of locations to the north and south of the Channel in the top 50 for tidal range. Some of those with the greatest tidal variations are either side of the Bristol Channel; Avonmouth, Weston-Super-Mare and Watchet to the south; Newport, Cardiff and Swansea to the north. Here the mean variation (the vertical difference between high and low tide experienced twice a day)­ is between 8-9m; tidal energy systems could exploit this rise and fall in sea levels to generate electricity predictably, quietly and sustainably.

Operating costs are among the lowest whilst their energy efficiencies are among the highest. The demand for clean energy means that tidal energy, with its massive worldwide potential, will continue to develop, both along existing traditional lines and, in the future, perhaps as ‘lagoon-less’ dynamic tidal power.

The moving currents themselves also provide a source of energy and a number of companies are engaged in exploring energy from tidal streams using under-sea turbines. The process is known as marine current energy and it’s the consistent predictability of those currents, the dense nature of water (to maximise turbine efficiencies), the ecological and environmental benefits and the desire to reduce carbon emissions and increase the contribution of renewables which is driving the research, developments and project installations.

KGAL has over two decades of experience in generating power from moving water; dammed storage, pumped storage, run-of-river and now tidal. One such tidal project is The Swansea Bay Tidal Lagoon; it’s an exciting new hydroelectric development for which we have been engaged by Atkins to provide the outline design for the eight sluice gates, stoplogs and associated hoisting gear.