Metro Mayor wants barrage to provide energy and to protect area from climate change effects
Artist’s impression of how the new Mersey Tidal project could look (Image: Liverpool City Region Combined Authority)
Development of a Mersey tidal barrage could provide vital flooding defences to properties across Merseyside as sea levels rise amid ongoing climate change. Since taking up the Metro Mayoralty in 2017, Steve Rotheram has championed the construction of the infrastructure in the historic River Mersey.
Stretching between Liverpool and Wirral, leaders believe that energy could power hundreds of thousands of homes and last for 120 years, while the project could create thousands of jobs along the way. It also opens the possibility of a first-ever cycling and pedestrian route over the river between the two boroughs.
Now, the potential to protect the region as climate change continues to impact water levels has been highlighted in new analysis to be presented to the Liverpool City Region Combined Authority (LCRCA).
The Mersey Tidal Power Project has commenced Phase 4 Development activity, that includes the consenting, engineering, project development and commercial activity. Although there has been interest and support in principle from the government, the Combined Authority is still working with various departments to secure support for development funding, which would enable the full business case to be developed.
It is hoped a full planning submission could be entered into this year with a view to work beginning in 2028. In an update on the project to go before CA members next week, the potential preventative capabilities have been highlighted.
The report said: “As part of the ongoing work in developing the project, studies have been carried out looking at the impact of flooding in the estuary following the publication of updated flood maps from the Environment Agency (2025) which account for sea level rise. The results have shown significant numbers of properties and critical infrastructure, predominantly in the middle and upper estuary, are already at risk of flooding from storm surges as well as surges in combination with high river flows.
“When incorporating climate change and sea level rise, the number of properties trebles with current flood defences unchanged. Modelling has demonstrated the ability of a barrage to provide protection from this flooding by significantly reducing the level of the incoming tide in the basin upstream of the barrage.
“By taking energy out of the system at the same time it also reduces levels slightly downstream of the barrage.” In November, it was revealed how South Korea’s national water management company could invest in the development in future.
K-Water, operators of the Sihwa Lake Tidal Power Plant, could look to put financial backing into the scheme as the business case progresses. The Metro Mayor signed a two-year extension to a memorandum of agreement with the South Korean company two months ago.
An original partnership was struck between both sides in 2022 to help shape plans to deliver the Mersey Tidal project. Detailed technical exchanges have taken place with K-Water and the lead contractor for the Sihwa Lake tidal plant, Daewoo E&C.
