At ICE and SWIP’s Enabling Better Infrastructure event in June, SWIP’s Peter Kydd, technical advisor to the Severn Estuary Commission and Strategic Advisor at WSP, detailed the trials, tribulations… and potential opportunities for long awaited projects to realise the clean energy potential of the Severn Estuary and Bristol Channel.
For over 90 years, people have been attempting to deliver projects that would harness the tidal power of the Severn. The Severn Estuary possesses the largest tidal range energy resource in the UK. The total contribution from projects in the Estuary could equal Hinkley Point C. It’s highly predictable, reliable and provides stability to the grid – and with a lifetime of over 120 years, it would lower wholesale electricity prices and reduce cost to consumers year on year.
Since 1933, more than 27 projects have been proposed – but, to date, nothing built. Tidal power is clean, reliable and, over the long term, reduces costs to the consumer. So why have tens of projects failed to deliver this?
As the body of water separating South West England from southern Wales, any project would need buy-in from a complex web of stakeholders – including a maritime community with a significant value chain; not to mention a complex and highly biodiverse natural environment.
But, with the appointment of the Severn Estuary Commission, supported by the Western Gateway, it seems thing are different this time around.
What’s changed?
With the goal to realise net zero by 2050 and the work of NESO to assess national energy needs, it is becoming increasingly evident that, as we electrify transport and heat, clean energy demands are on a steep upward trajectory. In fact, we’ll need more than double the electricity we are currently producing by 2050.
With the impacts of the war in Ukraine still costing most households more per month than pre 2019 levels, greater value than ever is also placed on the value of home-grown power. There is a strong rationale for indigenous power – and government recognises the need to prioritise UK sources of abundant clean energy.
The Western Gateway identified the scale of this opportunity in 2021 – with scene setting studies in 2023 and the Severn Estuary Commission appointed in 2024. They launched their report in March 2025 to the Welsh Senedd, and at the Houses of Parliament with a public launch at the ICE. The Commission’s work has attracted considerable interest in the national and local media and the next steps in the delivery of the Commission’s recommendations are being taken forward jointly by Cardiff Capital Regions and the West of England Combined Mayoral Authority.
One of the key conclusions from the Commission is that tidal lagoons rather than a large barrage provided a more acceptable means of delivering tidal power as they do not blockade the estuary.
The Commission’s approach: Environment first
The River Severn, is an important example of an estuary environment and it was vital to put the natural environment at the heart of the Commission’s work. To that end, three of the Commissioners were selected because of their environmental and sustainable development backgrounds.
WSP and APEM were appointed to produce a “no-holds-barred” report on the Severn Estuary’s environment. A workshop attended by environmental stakeholders and one to one consultations informed what was and what wasn’t possible.
The Commission also studied other aspects of tidal power development including engineering, grid connectivity, funding and finance and socio-economics before concluding that tidal power was feasible in the Severn Estuary. They made a number of recommendations, including:
- The smallest commercially viable lagoon should be the first project, developed using a public – private partnership approach and would help fill environmental data gaps and improve supply chain capacity;
- A spatial management plan for the estuary as a whole was necessary to achieve optimal environmental outcomes for all development proposals in the estuary – not just power.
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