A game-changing plan for a multi-billion point Mersey Tidal Power project could power one million homes and 500 football stadiums - and would put Merseyside at the forefront of the battle against climate change.

That is the message from Metro Mayor Steve Rotheram as he outlines the next step in the huge proposals to create either a barrage or a tidal lagoon in the River Mersey which would also create thousands of jobs.

After a year long study into the proposals, the Metro Mayor will today ask the City Region Combined Authority to commit a further £2.5m to carry out the next phase of work on the scheme and develop a preferred option for harnessing the renewable energy of the famous river.

He will also make a direct challenge to Prime Minister Boris Johnson to show he is serious about levelling up the country and tackling the climate crisis by backing a project that he says can provide clean, green energy for well over 100 years.

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The year-long study, led by Mersey Tidal Commission chair Brent Cheshire, has concluded that there is a strong case for taking the project forward to address potential future energy shortfalls, tackle the climate emergency, achieve zero carbon targets, and support a more stable renewable energy mix.

What the study found

-The UK’s demand for electricity is set to double by 2050 due to electric vehicles and as existing industries decarbonise

-Tidal power has a key role to play in meeting this demand from renewable sources, as fossil fuels are phased out

-Tidal power is predictable, flexible and reliable, complementing the intermittent nature of other major renewables like wind and solar power

-It could generate much more power than previously thought possible, with cutting edge turbine technologies now capable of generating power efficiently on both the ebb and flow of the tide.

-This flexibility in operation, with variable turbine speed and the ability to pump water efficiently, can help significantly in mitigating local environmental impacts

Liverpool City Region Mayor Steve Rotheram said:

“With demand for electricity set to double by 2050, the UK will face an energy crisis if the government doesn’t support large scale renewable projects like Mersey Tidal Power, which are key to keeping the lights on. 

“So far our work shows that Mersey Tidal Power could generate enough energy for up to 1 million homes, create thousands of jobs and make our region Britain’s renewable energy coast.

Metro Mayor Steve Rotheram is moving forward with plans for a Mersey Tidal project

“Our unique geography makes us one of the only places in the UK where it is possible to generate massive quantities of predictable, renewable tidal electricity. With the right government support, we could be generating clean power by the end of the decade – a full ten years ahead of the city region’s zero carbon 2040 target.

“But this will require Boris Johnson to not only talk about ‘levelling up’ the North, but to step up and address the imbalance in how major projects are assessed and funded. We know that Mersey Tidal Power has the potential to provide energy for well over 100 years, but the government’s current formula does not take that into account, instead using a 35 year timescale.

“So today, I’m calling on government to look seriously at our project and help us make this a reality. Not only will it help to make Britain a worldwide technological leader, but also a global leader in tackling the climate emergency.”

How could the Mersey Tidal Power options work?

Today's announcement from Mayor Rotheram is a significant step in the progress of the Mersey Tidal Power project, but there is a long way to go - and it will need government backing.

If the Combined Authority agrees to free up a further £2.5m - that money will be spent on working up more detailed plans and developing a preferred option for the project - which will be either a Tidal Barrage or a Tidal Lagoon.

Tidal Barrage

This is a phrase we have heard before when talking about harnessing the power of the River Mersey.

This option would see a dam-like structure used to capture energy from the masses of water moving in and out of the River Mersey's Liverpool Bay and its tidal forces.

Early diagram of how a Mersey Tidal project would work

Unlike a conventional dam, which would hold water on one side, a tidal barrage allows water to flow into a bay or river during high tide and release water during low tide.

This is done by measuring the tidal flow and controlling the barrage's sluice gates, where turbines are placed, to capture energy as the water flows out.

Tidal Lagoon

The other option being considered for the huge project is a Tidal lagoon.

This is another form of power station that  generates electricity from the natural rise and fall of the tides.

They work in a similar way to barrages by capturing a large volume of water behind a man-made structure which is then released to drive turbines and generate electricity.

The main difference between the two is that where a barrage structure spans an entire river estuary in a straight line, a Tidal Lagoon encloses a specific area of coastline with a high tidal range behind a breakwater - it is an option that is thought to be more considerate of the local environment.


It works by holding water back behind turbine gates as the tide comes in. The gates are used to control the flow of water into the lagoon and create different levels between the water in the lagoon and in the body of water around it (in this case the Mersey).

Then the gates are opened, water rushes into the lagoon and through the turbines to create energy and electricity.

Mayor Rotheram will spell out his vision for a Mersey Tidal project in more detail at an event this morning.