University of Liverpool engineers, working with marine research laboratory the Proudman Oceanographic Laboratory, found that four estuary barrages, across the Solway Firth, Morecambe Bay and the Mersey and Dee estuaries, could meet about half of the North West region’s electricity needs.

Professor Richard Burrows, of the Maritime Environmental and Water Systems Research Group, in the university’s department of engineering, said: “With concerns mounting over the UK’s future energy provision it will soon become paramount that all sources of renewable energy are fully developed. Unlike the wind, tides are absolutely predictable.

“The geographical location of the UK, and the seas that surround it, provide a great platform for marine renewable sources. The best places to harness tidal power at meaningful scales are areas with a high tidal range such as estuaries.”

The team used computer modelling to examine different types of tidal power, including barrages – which run from one bank of an estuary to another and guide water flow through sluices and turbines.

They found he most effective mode of generating electricity is “ebb generation”.

This collects the water as the tide comes in and releases it back through turbines once the tide has gone out.

“This water level difference across the barrage is sufficient to power turbines for up to 11 hours a day, and, in terms of the four North West barrages, the energy extracted could equate to 5% of the UK’s electricity generation needs,” said Professor Burrows.

The electricity generated would help the UK meet CO2 emission reduction targets, the researchers say.

They point out the barrages could also act as “substantial” sea defences and ease flood risks by draining the estuary after heavy rainstorms.

Joe Flanagan, head of energy and environmental technologies at the Northwest Regional Development Agency (NWDA), which funded the research, said: “The NWDA is pleased to have supported this project, which has provided an important stimulus to the concept of tidal power in England’s Northwest.

“Building on the work of the Liverpool team, I expect that a number of more detailed feasibility studies of individual schemes will be undertaken in the near future.

“Although most of the focus for tidal energy has been in the Severn estuary I would welcome the UK’s first major tidal scheme here in the Northwest.”

David Gibbs

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