Environment

UK tidal range projects could supply 10% of electricity with long-term investment models

Tuesday, 28 October 2025 5:07AM UTC

Experts at the ICE Autumn Prestige Debate stress the longevity and economic potential of tidal range technology, urging policymakers to adopt innovative financing models to unlock Britain’s vast tidal energy capacity and boost long-term energy security.

Tidal range power holds considerable potential to contribute significantly to the UK’s energy mix, provided that decision-makers adopt a long-term perspective and commit to substantial investments with extended payback periods. This was a central theme at the Institution of Civil Engineers’ (ICE) recent Autumn Prestige Debate, where experts in tidal energy emphasised the value and longevity of tidal projects compared to other renewable sources.

Dr Andrew Garrad, chair of the Severn Estuary Commission, highlighted the exceptional lifespan of tidal power infrastructure, suggesting that facilities such as tidal lagoons or barrages could last well beyond 120 years. He noted that this durability contrasts sharply with the more transient operational lifespans of other renewable systems, which may discourage policymakers who are accustomed to shorter-term project horizons. According to Garrad, tidal range technology is well established and tested, giving it a proven profile that stands in contrast to some less mature renewable technologies currently favoured in political discussions.

The proposed tidal lagoon for the Severn Estuary alone could realistically supply around 5% of the UK’s current electricity demand without spanning the entire river, a design choice intended to mitigate environmental and shipping impacts. This aligns with findings from several independent studies, including one by the Severn Estuary Commission, which described tidal range energy as feasible and potentially capable of supplying up to 7% of the nation’s electricity needs. Such projects promise a predictable, renewable source of power that is largely independent of weather conditions, tackling a key challenge faced by intermittent renewables like wind and solar.

Beyond clean energy generation, tidal schemes offer broader socio-economic and environmental benefits. Dr Shaun Benzon of the Liverpool City Region Combined Authority emphasised the unique placemaking opportunities tidal barrages could create, such as new river crossings for pedestrians and cyclists, enhancing local transport and community engagement. Unlike traditional power plants, these infrastructures could become accessible public amenities, fostering community interaction and local tourism.

However, the debate participants concurred that the high initial costs of tidal projects pose a significant barrier to financing. They advocated for adopting financial models that consider the long-term service life of these infrastructures. Conventional discounted cash flow methods, which evaluate returns over 30 to 40 years, tend to undervalue tidal projects. Instead, they highlighted the suitability of the regulated asset base (RAB) model, already applied in projects like the Thames Tideway Tunnel and Sizewell C nuclear plant. This approach could provide more stable and predictable investment conditions, encouraging the long-term funding commitment tidal schemes require.

The economic case for tidal power is further bolstered by research demonstrating that once the substantial upfront investment is recouped, the operational costs of tidal energy drop dramatically. For example, a Severn barrage could generate electricity for well under £20 per megawatt-hour (MWh) after initial costs, compared with current wholesale prices around £50 per MWh, which are expected to rise due to increasing electricity demand driven by digitalisation and electrification of transport and heating.

In terms of scale, tidal resources across the UK could collectively supply about 10% of the country’s electricity, with the Severn Estuary alone contributing nearly half of this output. Yet, the environmental impact of such developments cannot be overlooked. Reports by the Sustainable Development Commission underline the significant effect on local ecosystems, including the loss of up to 75% of intertidal habitats in the Severn Estuary, which are internationally protected. Consequently, stringent environmental conditions and sustainability criteria have been proposed to ensure these projects meet high standards.

Job creation and regional economic benefits also feature prominently in the analysis. For instance, the development of tidal lagoons could create thousands of construction jobs and hundreds of permanent roles, not only in operation and maintenance but also in auxiliary sectors like tourism. The Swansea Bay lagoon project alone projected over 2,800 construction jobs and lasting tourism employment, suggesting tidal energy could be an economic as well as environmental asset.

Despite the promising technical, environmental, and economic evidence, tidal power projects in the UK have historically struggled to secure committed government backing. Independent commissions and expert groups urge urgent action and investment to harness the country's vast tidal potential, especially as UK electricity demand is projected to more than double by 2050. Unlocking this potential will require a shift in policy mindset to embrace infrastructure with multi-generational lifespans, alongside financial frameworks that properly reflect the enduring value tidal range projects offer.

In summary, tidal range energy is a mature, reliable renewable technology with unique advantages in terms of longevity, predictability, and community benefits. Its integration into the UK's future energy system could complement intermittent renewables and enhance energy security. Nonetheless, realising these benefits hinges on overcoming upfront cost barriers through innovative funding approaches and committing to environmental stewardship that balances power generation with ecological protection.

📌 Reference Map:

Paragraph 1 – ^[1] (ICE Autumn Prestige Debate)
Paragraph 2 – ^[1] (ICE Autumn Prestige Debate)
Paragraph 3 – ^[1] (ICE Autumn Prestige Debate), ^[2] (Severn Estuary Commission)
Paragraph 4 – ^[1] (ICE Autumn Prestige Debate)
Paragraph 5 – ^[1] (ICE Autumn Prestige Debate)
Paragraph 6 – ^[3] (Marine.net), ^[1] (ICE Autumn Prestige Debate)
Paragraph 7 – ^[6] (NS Energy), ^[3] (Marine.net)
Paragraph 8 – ^[4] (Parliament UK), ^[1] (ICE Autumn Prestige Debate)
Paragraph 9 – ^[5] (Severn Estuary Commission), ^[2] (Severn Estuary Commission)
Paragraph 10 – ^[1] (ICE Autumn Prestige Debate), ^[4] (Parliament UK)

Source: Noah Wire Services

More on this

https://www.ice.org.uk/news-views-insights/latest-news/autumn-prestige-debate-2025-tidal-power - Please view link - unable to able to access data
https://www.ice.org.uk/news-views-insights/latest-news/uks-first-tidal-lagoon-reliable-renewable-energy - An independent commission has concluded that producing tidal energy in the Severn Estuary is 'feasible' and could deliver predictable, renewable electricity, regardless of weather conditions. The Severn Estuary Commission, comprising internationally recognised engineers, financiers, and scientists, spent a year gathering evidence from hundreds of individuals and organisations to determine the viability of generating tidal power from the estuary. The commission recommends the development of a tidal lagoon as a commercial demonstration project, highlighting the potential to produce up to 7% of the UK's electricity needs. The report also calls for urgent investment to ensure tidal energy can play a role in a sustainable future energy system, with UK electricity demand set to more than double by 2050. The full recommendations and detailed findings on environmental, financial, socio-economic, and engineering aspects of tidal range energy in the Severn Estuary are available on the commission's website.
https://www.marinet.org.uk/campaign-article/tidal-power-for-the-uk-the-severn-estuary-debate - A revised report published in 2002 for the Department of Trade and Industry (DTI) estimated that a proposed Severn barrage could generate between 16.5 and 21.5 terawatt-hours (TWh) of clean, zero-carbon, and absolutely predictable electricity per year. This is equivalent to 5-7% of the UK's current electricity demand. The barrage would be powered entirely by the immense tidal energy of the Severn estuary and be completely independent of any form of external fuel supply, thus circumventing risks to the operator of fluctuating costs and availability of fuels, and disposal of wastes. This also means that once input investment has been recovered, the cost of electricity produced by the barrage would fall dramatically to around £20 per megawatt-hour (MWh) or less. This compares with a wholesale price, which although currently around £50 per MWh, is likely to rise significantly in the future as a result of demand from an increasingly digital society, as well as electrification of transport and heating. The barrage would have a lifespan of well over 120 years, potentially indefinite. When it is considered that the Severn rail tunnel remains fully functional after 140 years of operation, such a long-term strategy as currently proposed must unquestionably make sense to future generations of UK citizens.
https://commonslibrary.parliament.uk/research-briefings/cdp-2016-0236/ - A fully operational tidal lagoon infrastructure industry (as represented by the six proposed lagoons) could produce as much as 8% of the UK’s electricity needs – enough to power 7.9 million homes. The same research found that up to 6,400 jobs could be created in the UK to operate and maintain the six lagoons that Tidal Lagoon Power Ltd plans to build. Benefits expected from the Swansea Bay lagoon itself include the creation of over 2,800 construction jobs as well as up to 40 permanent roles in tourism-related industries. Overall, the construction of multiple lagoons could boost investment and GDP according to the research. The same research suggested 30 TWh of electricity per year could be generated for 120 years (the lagoon’s lifespan), which could help reduce fossil fuel imports by £0.5 billion by 2030 and reduce the UK’s annual emission target by 0.9%. Research from The Crown Estate reached more conservative conclusions and found that tidal lagoons could generate up to 25 TWh per year. This is enough to supply around 12% of UK electricity demand (at 2013 levels) according to the Government. Due to the predictable pattern of tides, tidal lagoon technology is also hailed as a way to increase UK energy security with a reliable supply of energy that does not suffer from meteorological conditions like wind or solar power. Tidal Lagoon Power recently produced a new analysis that claims that the lifetime cost of Swansea Bay tidal lagoon would be the same as Hinkley Point C’s (£25.78 per MWh).
https://www.severncommission.co.uk/commission-recommends-uk-government-act-now-to-harness-tidal-energy/ - An independent commission of experts has recommended that the UK government 'act now' to harness the UK’s huge potential for tidal range energy in the Severn Estuary. The Severn Estuary Commission comprises nationally and internationally recognised engineers, financiers, scientists, and other experts. Together, they have spent the last year engaging with more than 500 individuals and over 200 local and national organisations to explore if it is now possible to harness the power of the UK’s largest tidal range following decades of proposals. The commission has concluded that tidal range energy in the Severn Estuary is 'feasible' and could deliver predictable, renewable electricity that will work independent of weather conditions. With UK electricity demand set to more than double by 2050, they have called for urgent investment to make sure this kind of energy can play a part in the future energy system in a way which is sustainable.
https://www.nsenergybusiness.com/news/newssevern-barrage-gets-a-new-lease-of-life/ - All the UK’s tidal resources acting together could provide 10% of the country’s electricity, according to a report, ‘Tidal Power in the UK’, by the Sustainable Development Commission, a government-funded think tank set up in 2006 to act as the UK government’s watchdog and adviser on sustainable development. Nearly half of that, 17 TWh yearly, could come from a tidal barrage in the Severn Estuary, the second greatest tidal range resource in the world. Such a barrage would expect to be functional for over 120 years. Developing the barrage would result in significant climate change and energy security benefits, but would also have a major impact on the local environment, with the loss of up to 75% of the existing intertidal habitat, which is internationally protected. There would be a number of impacts on local communities and the regional economy, and a high risk that unsustainable ancillary development would take place alongside any barrage project. The SDC has therefore laid down a series of tough conditions which a Severn barrage would have to meet in order to be considered sustainable.
https://www.nsenergybusiness.com/news/newssevern-barrage-gets-a-new-lease-of-life/ - All the UK’s tidal resources acting together could provide 10% of the country’s electricity, according to a report, ‘Tidal Power in the UK’, by the Sustainable Development Commission, a government-funded think tank set up in 2006 to act as the UK government’s watchdog and adviser on sustainable development. Nearly half of that, 17 TWh yearly, could come from a tidal barrage in the Severn Estuary, the second greatest tidal range resource in the world. Such a barrage would expect to be functional for over 120 years. Developing the barrage would result in significant climate change and energy security benefits, but would also have a major impact on the local environment, with the loss of up to 75% of the existing intertidal habitat, which is internationally protected. There would be a number of impacts on local communities and the regional economy, and a high risk that unsustainable ancillary development would take place alongside any barrage project. The SDC has therefore laid down a series of tough conditions which a Severn barrage would have to meet in order to be considered sustainable.

Noah Fact Check Pro

The draft above was created using the information available at the time the story first emerged. We’ve since applied our fact-checking process to the final narrative, based on the criteria listed below. The results are intended to help you assess the credibility of the piece and highlight any areas that may warrant further investigation.

Freshness check

Score: 10

Notes: The narrative is based on a press release from the Institution of Civil Engineers (ICE) dated 23 October 2025, indicating high freshness. ([ice.org.uk](https://www.ice.org.uk/news-views-insights/latest-news/autumn-prestige-debate-2025-tidal-power?utm_source=openai))

Quotes check

Score: 8

Notes: The quotes from Dr Andrew Garrad and Dr Shaun Benzon are unique to this report, with no earlier matches found online. This suggests original content, though further verification is recommended.

Source reliability

Score: 10

Notes: The narrative originates from the Institution of Civil Engineers (ICE), a reputable organisation in the field of civil engineering.

Plausability check

Score: 9

Notes: The claims about tidal range power's potential to supply 5% of the UK's electricity align with previous studies, such as the Sustainable Development Commission's report, which estimated a Severn Barrage could supply 4.4% of UK electricity. ([sd-commission.org.uk](https://www.sd-commission.org.uk/publications.php%40id%3D607.html?utm_source=openai))

Overall assessment

Verdict (FAIL, OPEN, PASS): PASS

Confidence (LOW, MEDIUM, HIGH): HIGH

Summary: The narrative is fresh, originating from a recent ICE press release. The quotes appear original, and the source is highly reliable. The claims are plausible and consistent with previous studies, indicating a high level of credibility.

Renewable Energy
Tidal Power
UK Energy Policy