New tidal barrage could link Wirral and Liverpool

A proposed tidal barrage for the Mersey could provide a major new link between Wirral and Liverpool, according to a new report.

The Liverpool City Region Combined Authority report, seen by the LDRS, outlines various plans for a potential tidal barrage project, which could be built across the Mersey, a long-term vision that is considered crucial to reducing carbon emissions across Merseyside. If it goes ahead, the multi-billion project is expected to power one million homes and create thousands of jobs.

The combined authority hopes to have the project delivered by 2040 to operate for 120 years alongside four new offshore wind developments expected to be up and running by 2030 – although this will require substantial government backing.

The report includes new illustrations of what a potential barrage in the Mersey could look like, with references to street furniture, cyclists, and “rest points along the route”.

One CGI mock up includes people walking and cycling across the barrage between Liverpool and Wirral,  but it is understood no decisions have been made about the project, including its design and whether it will in fact be a barrage or lagoon.

The report published in October said the project would be “a first of a kind project in the UK, and involve constructing a barrage with turbines, sluices and marine navigation locks in the Mersey.

It adds, “The engineering, manufacturing and construction would be the largest project in the North West and be a bold statement of our ambition to address the climate change challenges of decarbonising our electricity system by using clean renewable energy and responding to the flood risks posed by sea level rise.

“We need more electricity to enable heating and transport to decarbonise and move away from fossil fuels, and we need it local to our demand.”

The report adds, “A tidal project on the Mersey will create a major new piece of infrastructure – linking the left and right bank (Wirral and Liverpool) – with the potential to provide more clean energy, provide protection against inevitable sea level rise and can be deployed to help create and enhance natural habitats. This will require assessment and agreed mitigation plans.”

The report said the tidal range turbines proposed would have the capacity to generate 25 megawatts each with 28 turbines. The turbines will generate electricity by turning as the tide goes out and comes back in though sluice gates would also be used to let water quickly pass through the barrage if needed.

The report cites two existing tidal barrages as examples to draw potential inspiration from. These are the La Rance barrage in France, which boasts 24 turbines and is 750m long and the Sihwa plant in South Korea, which has 10 turbines and is part of a 12km road.

In December 2022, Liverpool City Region Mayor Steve Rotheram signed an agreement with South Korea’s state water company to co-operate and share lessons that could help the region develop the scheme.

However for the project to progress, the report said there needs to be government support for tidal range technology, funding, a financing bill, and a “common approach” to sea-bed leasing to avoid the high costs some offshore wind farms face.

The report recommends the combined authority’s devolution agreement should be extended to explore tidal range power, secure development grant funding support, and build a supply chain and manufacturing base in the north west.

In the report, Liverpool City Region Mayor Steve Rotheram also said, “For as long as I can remember there has been talk of building a tidal barrage on the River Mersey and, thanks to devolution, we’re working to make it a reality. I want to harness the potential of our great river, which has been the lifeblood of our region’s fortunes throughout its past to power our future.”

Wirral Council will vote next week on a motion referring to the report brought forward by its Liberal Democrat councillors. If passed, the motion will ask the local authority’s regeneration director to ask for technical information as councillors are “anxious to secure more details on the project over and above” those in the report.

Councillors are keen to see the latest version of the scheme, likely costs and funding, where it will go, and potential effects on wildlife with a presentation to all councillors.

Liberal Democrat leader Phil Gilchrist who put forward the motion said, “I do give it a guarded welcome but there is a lot of work to do before it gets off the drawing board. On the face of it there is hardly anything for the public to get their hands on to study properly. With something on this scale, this has to be sorted out.”

He added,“Certainly there is a vision. We do need to know if there are any drawbacks. These might involve silting up, channels for shipping, and impacts on wildlife.”

A Combined Authority spokesperson said, “Mersey Tidal Power has the potential to provide enough clean, predictable and renewable energy to power up to one million homes for 120 years and create thousands of local jobs, apprenticeships and training opportunities in construction, science, research and development.

“Once operational, it could make the Liverpool City Region a worldwide centre of excellence in a key industry of the future and secure the UK’s reputation as a global leader in green energy.

“With an abundance of existing natural strengths and assets in wind, hydrogen and solar energy, this scheme forms a key part of Mayor Steve Rotheram’s ambitions to position the Liverpool City Region as Britain’s renewable energy coast.

“As such, the Mayor has tasked the combined authority with assessing the technical, environmental, ecological and cost implications of delivering the project, which resulted in the Liverpool City Region signing an agreement with South Korea’s state water company K-water. K-water operates the world’s largest tidal power scheme and has agreed to co-operate and share lessons to help our region develop Mersey Tidal Power.

“A project of this scale takes time to plan and exploration work to determine the operating model is still ongoing. However, Mayor Rotheram has been clear throughout that, in order for Mersey Tidal Power to become a reality, the Liverpool City Region is reliant on the government to match our ambitions for the project with the appropriate level of funding support.”

Image: An artist’s impression of the project included in a report about the Mersey tidal power project. Credit: Liverpool City Region Combined Authority

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