The Swansea Bay Tidal Lagoon is oven ready – it’s time Labour acted
Sam Bennett, Welsh Liberal Democrat Councillor for Waterfront in Swansea & Senedd Candidate for Gŵyr Abertawe
In 2018, the Conservative government pulled the plug on the Swansea Bay Tidal Lagoon. With the stroke of a pen, Conservative ministers cancelled what would have been the world’s first purpose-built tidal lagoon power station; an oven-ready project with planning consent, local backing, and international significance.
Seven years later, the verdict is in: that decision was a monumental mistake.
The newly published Severn Estuary Commission report confirms what the Welsh Liberal Democrats have argued all along. Tidal lagoon power in the Severn Estuary is feasible, valuable, and strategically important. Crucially, it concludes that tidal lagoons, not mega-barrages, are the right way to unlock that potential. In other words, the very model Swansea Bay pioneered was the correct one.
Yet instead of leading the world, the UK is still talking. And Swansea is still waiting.
When the Conservatives cancelled the project, they claimed it was “too expensive” and “poor value for money”. What they failed to account for was value in the round: long-term energy security, industrial regeneration, grid stability, and the chance to build a global export industry in Wales. The Severn Commission now makes clear that tidal lagoons offer predictable, low-carbon power with system benefits wind and solar alone cannot provide. Had Swansea Bay been built, it would already be generating clean electricity today, while providing exactly the kind of firm power South Wales now desperately needs.
The lost time is staggering. Swansea Bay was not just a power station; it was a pathfinder. As the Hendry Review recognised, it was designed to prove the technology, build supply chains, and pave the way for future lagoons across Wales, from Cardiff Bay to the North Wales coast. Instead, Britain ceded first-mover advantage. Manufacturing capability identified for Swansea has withered. Expertise has drifted overseas. And a technology Wales could have led is now being explored elsewhere.
The Conservatives must own that failure. Their decision in 2018 did not save money; it squandered opportunity. It denied Swansea thousands of construction jobs, long-term skilled employment, and billions in economic value. At a time when Swansea Bay needed investment and confidence, Westminster slammed the door shut.
But it is not only the Conservatives who must answer questions. Welsh Labour was vocal in opposing the cancellation. They rightly criticised the decision and spoke passionately about the damage it would do to Swansea and to Wales’s green ambitions. Yet now Labour is in government at UK level, they have refused to revive a project that is effectively ready to go. As often with Welsh Labour, warm rhetoric isn’t backed up by concrete action.
That contradiction cannot be ignored. If Labour believed Swansea Bay was the right project in opposition, why is it still off the table in government? The Severn Estuary Commission explicitly calls for a commercially viable tidal lagoon as a demonstration project. Swansea Bay already fits that description. The planning work has been done. The public support is proven. The case is clearer now than it was in 2018.
Meanwhile, South Wales faces a new challenge: powering the industries of the future. Data centres, electrified steelmaking, battery manufacturing, and green hydrogen all demand reliable, low-carbon electricity at scale. Wind and solar are essential, but they are not enough on their own. Tidal lagoons generate power every day, in winter as well as summer, independent of weather systems. That predictability is exactly what energy-hungry industries need if Wales is to compete.
Rebuilding Swansea Bay Lagoon would send a powerful signal: that Wales is open for green investment, serious about energy security, and ready to lead again. It would provide a major economic boost to Swansea and the wider Bay region; creating jobs, anchoring skills, and restoring confidence after years of drift.
The Welsh Liberal Democrats are proud to have championed the Swansea Bay Tidal Lagoon in government and out of it. We believed then, and we believe now, that it represented the best of Welsh ambition: innovative, sustainable, and rooted in local benefit. The Severn Estuary Commission has vindicated that view. The question is whether today’s governments have the courage to act on it.
We will continue to call on the UK Labour government to do what the Conservatives would not: revive the Swansea Bay Tidal Lagoon as an oven-ready project, backed by a modern financing model and national policy support. And we call on the Welsh Government to press relentlessly for its delivery, not just in principle but in practice.
Wales had a chance to lead the world once. We cannot afford to miss it again.
Support our Nation today
For the price of a cup of coffee a month you can help us create an independent, not-for-profit, national news service for the people of Wales, by the people of Wales.
I,first came across tidal power for the UK in 1977. That was the the La Rance tidal power station had been generating power for eleven years. Forty nine years later La Rance is still generating electricity.
Swansea tidal lagoon is decades overdue.
La Rance ruined the local ecology. Never properly studied.
If it was never properly studied how can you know it ruined the local ecology?
Well said! A hit, a palpable hit!
Play nicely
I bet tuppence on the little one!
I said “properly” studied in the way that environmental impact studies are required these days. There’s plenbty of evidence of environmental harm. Look at Wikipedia for a start.
This is all wikipedia has to say on the Rance tidal barrage: “The barrage has caused progressive silting of the Rance ecosystem. Sand-eels and plaice have disappeared, though sea bass and cuttlefish have returned to the river. By definition, tides still flow in the estuary and the operator, EDF, endeavours to adjust their level to minimize the biological impact.” I wouldn’t call that “plenty of evidence of environmental harm”; the silting referred to would be a natural process in many river estuaries anyway, that is why Carmarthen is no longer a port. I would also point out that the Swansea scheme is a lagoon, not a barrage; an important… Read more »
I said look at Wikipedia for a start. Look further…
This concept is back on the agenda elsewhere too: https://www.theguardian.com/environment/2025/dec/27/london-eye-architect-proposes-14-mile-tidal-power-station-off-somerset-coast
The original proposal was undoubtedly expensive for consumers given the level of subsidy demanded; but what happened to the latest version of this project led by an outfit called DST or was it just empty PR by the Council?
It looks cheap by today’s wholesale prices.
The latest project was supposed to consist of incremental developments: various solar projects; battery production and storage; hydrogen production and use; etc. A tidal lagoon would have been an optional extra at the end. All talk, of course, by developers looking for massive public subsidies. Expect it to be revived at election time…
They look expensive but you kind of have to factor in that most of those costs won’t be recouped for decades for the developers. At least they won’t see any real profits until the work has been completed.
Several factual errors in that article:
1. Tory Gov didn’t “cancel” the project. They granted development consent but declined to subsidise it to the extent demanded by the developer (because it didnt make economic sense – and trickle of intermittent and variable electricity at huge expense).
2. Welsh Gov might be in favour of tidal power in principle but it didnt approve (via NRW) the Marine Licence required by the project – mainly on grounds of likely fisheries impacts.
Extracting energy from the tides should be a no brainer. If you don’t like the proposed financials, propose a better model. Only those profiting from oil and gas could have any objection to that.
Point you are missing is that the subsidy ends up on your utility bill and mine. Hardly likely to be welcomed by those struggling with energy costs. It’s all academic in all probability because Welsh government will never grant the marine licence (captured by environmental lobby) and government is too risk averse to grip it all.
Point you are missing is there should be a model without subsidy. Think about all the efforts to locate, extract, transport, store and distribute gas before it can generate power. None of that’s needed in a lagoon that’s nothing more than a sea wall and turbines.
“nothing more than a sea wall and turbines”, which is hugely expensive to construct in a location with a high tidal range, and which causes significant environmental harm to generate an insignificant amount of electricity.
A tidal lagoon of this size does not cause “significant environmental harm”, and 300+ Mw. of electricity is not insignificant.
You’re showing your ignorance.
320MW was the maximum capacity of the generators, not the amount of electricity to be produced. Estimated annual generation was about 500GWH, making average generation less than 60MW. 500GWH was about 0.15% of UK requirement in 2015. Less now, even less in future. Insignificant.
The project failed to get a Marine Licence because of the anticipated environmental harm.
Gentle reminder it was a small easy one that would lead the way to several much larger versions.
And the marine licence wasn’t rejected, it was still in the determination phase when the project was shelved.
I know what the developer claimed. Much of it was delusional.
The ML application was actually treated by NRW as withdrawn because of the applicant’s failure to produce requested evidence.
You can’t have it both ways. Any private sector initiative has to tell a good story to get attention. And it has to promise attractive returns to lure investors away from safer investments. It would’ve been much better if the UK Gov wasn’t blinded by their carbon masters and had the vision and ambition to build this itself then sell the completed asset to a pension fund. But we have the worst of all worlds where government isn’t bold enough to do it in-house yet isn’t willing to take a punt on the private sector doing what the private sector… Read more »
The same ‘ insignificant ‘ amount of energy as the Small Modular Reactor proposed for Wylfa. That itself untried technology, producing significantly more nuclear waste per unit of output than the large model and with an untested and problematic waste management. It is expensive to build and requires subsidies for many years.
It’s not problematic… it’s all actually incredibly simple. We know how to manage nuclear waste safely and as the years pass by we’ve even learned to recycle nuclear waste and produce less of it in the first place. Of the things we have to worry about, nuclear waste is not it. It’s tiny in comparison to everything else. I’ll admit some people get itchy about it (unnecessarily so) but we can handle it. SMR more so than say Nuclear Submarine reactors or the older power plants. As for ‘more waste per unit’… honestly, I’m pretty sure that Anglesey all turned… Read more »
You are quite wrong with your blase approach. SMRs are not a smaller version of the present models, they are a different technology and the waste is chemically different and more toxic. Studies by Stanford University, among others, have pointed to many problems. If it is such a brilliant concept, why is it that the only ones that have actually gone beyond the development stage, are in Russia and China. They have higher neutron leakage than the large reactors, contaminating infrastructure and water and the are not particularly efficient, on a par with floating wind turbines. The SMR on Yns… Read more »
Wrong.
Proposed Wylfa capacity is apparently 3 x 470MW = 1,410MW.
Capacity factor for nuclear is about 90% = about 11,000GWH per annum.
Swansea Bay capacity factor less than 20% = about 500GWH per annum.
The official proposal for Wylfa is up to three reactors. The cost has already risen from the original £1.8 billion quoted by Rolls Royce, to £2.5 billion and with the construction period estimated as 10 to 15 years it is unlikely to stay at that cost. The rhetoric regarding speed of construction is also questionable as the experience of those constructed in Russia and China and those in late stage development in Argentina, has shown significant overruns. As for capacity, that will not only depend on the plant itself, but on grid capacity. With an ever increasing renewable output, it… Read more »
Ok, that’s an argument about nuclear. Im not getting involved because I dont know much about it. I wish people who know hardly anything about tidal lagoons would do the same.
Define “environmental harm”
The problem is distinguishing environmental change from environmental harm. The Gwent Levels are celebrated as a nature wonderland yet they are an entirely human construction when the salt marshes were drained for farmland and sea defences were built. The original ecology was certainly “destroyed” but nature adapted and no environmentalist is today demanding to let the sea back in.
Why? Don’t you understand the concept? Or haven’t you studied the Swansea Bay details. Get reading…
The evidence is against you. If there was a model without subsidy it would have been built by now.
The problem with all this expensive green subsidy isn’t the engineering or the willingness for private sector to invest, it’s the way Whitehall manages risk. They force the private sector to take huge risks for which the expected rewards must be very high. Whitehall could instead choose to develop projects like this itself, putting the construction out to tender, sorting out the planning and connecting it to the grid. Once generating power and the numbers are known the finished asset can be sold to the highest bidder so it doesn’t add to public debt. The private sector can then operate… Read more »
You are correct; but alas, that isn’t how Whitehall operates. The culture is one of keeping all risk at “arms length”. The only possibility is a project in England anyway as Welsh Government/NRW will never grant a licence.
We need to completely rethink how we fund and run critical national infrastructure.
I agree. Such projects, like housing, trains, buses etc., should be both built and run on a non-profit basis (like Dwr Cymru) by the state , for the benefit of the whole population, not for a few shareholders.
Indeed. Need to take the politics out of it and look to Singapore, a supposed neoliberal nirvana where the state owns 80% of residential housing and majority stakes in the airport, business and industrial parks, airline, ports, transit network, utilities, plus the largest bank and mobile network, totalling over 500 government-linked companies
Need to take out the profit, the risk to public funds and the risk to the environment. Honour the WFD and The Habitats Dir.
Didn’t we leave the EU?
You really don’t know much about this sort of thing do you. Google ‘retained EU law’.
52% voted to return to the dark ages. You need to accept democracy.
You have no idea what I think about Brexit. Don’t try to lecture me about democracy.
We need to rethink how we DEFINE critical national infrastructure…
Is there any definition where national energy infrastructure isn’t critical?
It should apply to any class of asset that would have a significant detrimental impact the economy and/or national security if it failed or became unreliable.
Imagine the impact if Heathrow closed tomorrow. Only a mad government would allow that to be entirely owned by the private sector. Not even the US, home of the free market, allows this.
So you are advocating building at the public expense, then handing it over to the private sector to reap the profits? Isn’t that what Thatcher did, and look at the results of that.
It’s the lesser of two evils. What happens today is we commit to buy power from privately funded projects at sufficiently inflated prices to encourage these projects to happen. That means we all pay over the odds for the energy for the life of the scheme which might be decades. The alternative is government borrows short term to build it them pays off that borrowing by selling it to a private owner who then sells us the power for decades at whatever the market rate is. You could make an argument to keep the assets on the books but we… Read more »
Tbh, it should be managing the infrastructure in house entirely from design, to construction and indeed operation, lending experts when things aren’t being built to other countries where things are being built as and when required.
If the private sector want a cut, then they can build their own nuclear reactors.
Rightly or wrongly we currently live in a world where public debt as a share of GDP is used to measure how expensive it is for government to borrow money. The interest paid on that debt is money that can’t be spent on public services. Owning everything would be lovely but the interest payments which are already over £100bn would be impossible to service.
There is ‘transporting’ and ‘storing’ plenty of people protesting about pylons… okay I say plenty, there is Bob and Karen from a remote farm in North Wales…
.
Hm… subsidizing Big Oil’s agenda via increasing their bumper profits… cheap sure, but causes dirty polluted air. Lets not say anything about oil and fossil fuels getting more and more expensive… vs… sustainable, minimum effort, constant energy supply…
You know… I think we can handle it.
I don’t disagree; but after 25 years of committees, studies and largely empty rhetoric on barrages, lagoons and mini lagoons, the only logical conclusion is that it won’t happen.
You need to distinguish between tidal range and tidal stream. The latter appears to be viable. The former (lagoons) is not a “no brainer”. It’s a non-starter. It doesn’t make sense on any level and the current proposals (West Somerset, etc) will come to nothing.
The tide goes up, the tide goes down. Tapping into that to generate power shouldn’t be difficult. This proposal was described as a pathfinder to lead to much larger projects once it had satisfied the sceptics.
Simplistic. I know quite a bit about the Swansea Bay proposal and you haven’t got a clue about the issues involved.
Your assumption that only easy and cheap projects should be supported is lazy and dangerous.
The reason we are in this energy nightmare is because we overdosed on gas generation because it was easy and cheap. Until it wasn’t.
We need energy independence and a diversity of sources.
You have no idea what I assume… And your ‘lazy’ comment is insulting. How much time have you spent studying tidal lagoons..? Not as much as I have, I’m sure…
Your bluster conveniently let you misdirect the points raised.
One expert in tides and coastal processes told me that he expected the Swansea Bay turbines (set in the sea bed and operational for about 13 hrs per day, in 4 blocks, therefore inactive about 11 hrs per day) to be buried by the first big storm…
Just like the nearby port that blocks up at the slightest breeze?
No, nothing like local ports.
[You do realise that the local ports were only kept open with dredging?]
Daily?
“Intermittent” “variable”…. Sir… they are tides. Unless you’re planning on blowing up the moon? They come at least twice a day and generate energy constantly (it’s literally how the lagoon works, water is always, all the time, flowing.)
Tidal energy is second only to Nuclear in terms of reliability. Might not generate quite as much but it also won’t go boom.
You’re plain wrong. Swansea Bay would have generated in 4 blocks per day, about 13 hrs total, about 11 hrs with no generation around high and low water. Also huge variation between generation on neaps and on springs.
All entirely predictable years in advance.
You accept that your ‘constant’ generation claim was wrong?
Wrong poster. No generation source is constant, as maintenance and variable fuel costs put paid to that even for gas and nuclear. Reliable and predictable is as good as it gets.
Sorry. You’re right, it was Smae who made the ‘constant’ claim.
Tidal probably is viable, but why should Wales fund the development costs? The UK has an obsession with being first, mature economies like France are doing their equivalents of Crossrail ((£3bn over budget) and Nuclear New Build (Sizewell C in 2025 was rebudgeted https://www.bbc.co.uk/news/articles/cev03wer0p2o.amp) after England has delivered; plus French companies such as EDF, Vinci and Alstom are using French speaking staff to deliver UK projects and then they can return to France with experience. Is Swansea University involved, or will all the well-paid professional services jobs be in England? The attached article shows tidal power schemes have not been… Read more »
Tidal stream might be viable. Tidal range is not. Too expensive and too harmful for the small amount of electricity produced.
The article you quote shows the opposite of what you claim , and is very positive on the future of tidal power.
Labour action is an oxymoron
It’s rare for Parliament/Senedd/Government to ever be associated with ‘action’. I don’t think it’s anything to do with Labour.
One person’s “action” is another person’s “lack of due diligence” spending taxpayer’s money.
Oven ready? Oh we’ve heard that kind of talk before…
I haven’t normally got much time for this fella but in this case he’s talking from a position of detailed knowledge…
https://nation.cymru/opinion/saying-no-to-the-swansea-bay-tidal-lagoon-was-not-a-failure-of-ambition/