Government pledges to work with tidal range sector to explore its potential

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The promise came as a result of a Parliamentary debate on the topic held on 10 January. It said it will now work with the sector to model the potential benefits and collect an evidence base to build upon.

Tidal range involves building a barrage across a river or estuary, or a lagoon in a bay, then using the tides to create a water level difference on each side. This stores up potential energy, which is then used as the water is allowed through the wall, again spinning turbines to generate power. The bigger the difference between water levels on each side, the bigger the amount of potential energy.

This is different from tidal stream technology which captures kinetic energy by placing turbines in a water column – similar to how wind turbines work.

Tidal range is the technology that has the potential to provide a greater contribution to the UK energy mix, with some proposed schemes having GW capacity. The UK is also blessed with the second highest tidal range in the world, making it an ideal place for such schemes.

Proposed tidal range projects on the west coast of England and Scotland

However, there has not been much governmental support for tidal range technology thus far except for a passing mention to “aggressively explore” opportunities in the British Energy Security Strategy. It was entirely excluded from the Energy Act 2023.

What has held back tidal range projects is the cost and timescale for construction, as well as relatively unproven technology (although there are examples overseas of successful schemes).

This may be about to change following this week’s parliamentary debate.

The motion was brought forward by Labour MP for Birkenhead, Mick Whitley, who reiterated the potential of tidal range projects in the UK and added that “the government’s ambition in supporting the development of new tidal range projects has been sorely lacking”.

He mentioned that the sticking point for tidal range projects has been the government’s insistence that they provide value for money.

Whitley brought up the 320MW, £1.3bn Swansea Bay tidal lagoon, which was the only tidal range project that has been granted a development consent order (DCO) in the UK. However, that was granted in 2015 and because work didn’t start on site within five years of receiving the DCO, the permission lapsed.

Whitley cited University of Birmingham research that suggested that the Swansea Bay lagoon would have made a return on the investment.

“The Government’s decision not to provide support for the Swansea bay project seems to have been seriously misjudged,” Whitley added. “It has deprived us of a credible pathfinder project.”

He continued on to say that, considering the crucial role that tidal range could play in the battle against climate breakdown, “the fundamental question of value for money needs revisiting”.

Witley continued: “Principally, that means adopting a whole-systems approach when assessing cost-effectiveness. The levelised cost of energy can be a useful tool, but it can also be a blunt instrument when it comes to gauging the comparative costs of renewable and low-carbon energy sources that fails to take into consideration the additional costs of solar and wind generation caused by grid transmission constraints, rebalancing and storage.

“It also fails to account for the fact that, uniquely for a renewable, tidal energy is a timetabled predictable resource, giving it an important role to play when seasonal factors interrupt supply from solar and wind. In my previous engagements on this issue, I have made the case that when a whole-systems analysis is made, the costs of tidal power are comparable to offshore wind and new nuclear.”

Facing the issue of cost of tidal range projects head-on, Whitley admitted “we will of course need to consider the optimum financing arrangements for new tidal range projects”. He suggested that “the government needs to be working with the industry to look seriously at the merits of employing a regulated asset base model for funding tidal range, just as [it] did last year with nuclear”.

He continued: “There is considerable enthusiasm in industry to develop our tidal range capacities, but investor confidence remains low, largely because of a widespread—and I am afraid, for the time being, legitimate—concern that developers will not have the government support.”

Whitley then moved on to specifically discuss the Mersey Tidal power project, a project in the Mersey Estuary being developed by the Liverpool City Region Combined Authority (LCRCA). A document released last November suggested it would be a 700MW capacity scheme that would also link the Wirral and Liverpool while providing protection against sea level rise.

“The project represents an unparalleled opportunity for our region,” he said. “It has the potential to provide a predictable domestic green energy supply to a million homes on Merseyside and to create thousands of new jobs, including in my constituency of Birkenhead, while supporting hundreds of UK companies across the supply chain. If delivered successfully, the Mersey tidal power project would undoubtedly be transformative for our region, but its impact would also be felt nationwide, helping to bring us closer to achieving our legally binding targets to reach net zero carbon emissions by 2050.”

He continued: “The Mersey is a relatively short estuary with shallow waters, and this geography makes the area the ideal location for a commercial pilot project of the kind that industry figures believe is essential to accelerating progress in this sector. By assigning the Mersey tidal power project pilot status, the government could begin to resolve issues around regulation, planning restrictions and environmental impact before turning their attention to larger gigawatt-scale schemes such the Morecambe tidal barrage.”

Whitley said that “we need to see the government working as an active collaborator with the LCRCA as well as industry”.

During his speech, Whitley received support from Liberal Democrat spokesperson for environment, food and rural affairs Tim Farron and the Democratic Unionist Party health spokesperson Jim Shannon.

The government’s response in the debate came from parliamentary undersecretary of state for energy security and net zero Andrew Bowie.

“To deliver [emissions] targets and provide long-term energy security, we must consider all of the tools available to us,” he said. “Tidal range […] provides yet another domestic energy source to our growing list of renewables. It also shows promise as a large-scale, fully predictable and non-weather-dependent source of power. Tidal range, as everybody in this room knows, could yield energy-system benefits by balancing the grid against variable renewable sources such as wind and solar. Additionally, with sites of suitability being close to centres of high demand, such as Liverpool, tidal range could circumvent the need for extensive grid connections.”

Bowie said that “officials in the Department are […] aggressively exploring the options for tidal range in the future by working with the sector to model the potential energy-system benefits of tidal range and establish an evidence base to build upon”.

He then pledged that “officials in the Department for Energy Security and Net Zero will continue to engage closely with the sector throughout this process and will communicate their findings, when appropriate, to the sector and indeed to Members of this House”.

He added: “As a nation surrounded by water, we will continue to work with the sector, and with Members interested, to explore and take advantage of the opportunities presented by tidal range to provide clean and secure renewable energy.”

Following the debate, LCRCA project director – tidal power Martin Land said that today, 11 January, the Authority had received a letter from energy security and net zero secretary Claire Coutinho “offering further discussion” on the Mersey tidal proposal.

The Mersey Tidal project is touted to be the biggest engineering project in the North West. A response to a freedom of information request published this week said that it is expected to take seven to 10 years to construct. LCRCA hopes to have it online by 2040.

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