An independent commission set up to assess the potential for tidal range renewable projects in the Severn Estuary has reported its findings.

The Severn Estuary Commission, funded by various organisations including The Crown Estate, rejected proposals for a large barrage across the estuary and said that governments should focus on supporting smaller projects to capture the power of the vast tide range.

The Commission was set up by the Western Gateway partnership, a coalition of politicians, business and public sector leaders and academics covering an area stretching from Swansea to Swindon and straddling the Severn. The Western Gateway partnership, a non-statutory body, appointed Dr Andrew Garrad to chair the Commission.

The Severn Estuary is home to the highest tidal range in Europe with some estimates suggesting it can provide between 5 and 7% of the UK’s electricity needs.

Striking a balance

The assessment of the feasibility of tidal energy schemes within the estuary is not new – the  Sustainable Development Commission in 2007 released a comprehensive report and ten years later the ‘Hendry Review’ was published, among numerous other studies.

Earlier proposed schemes have not been taken forward, despite extensive feasibility work, amid opposition due to the impact on bird life in the Estuary, the impact on the port at Bristol, as well as the cost.

Annie Smith, of RSPB Cymru, said at the time of the launch of the Commission that it must strike the correct balance when setting out its work. “The huge tidal range that makes it [the Severn Estuary] such a high energy system also makes it globally important for wildlife, providing vital habitats for tens of thousands of wading birds and water fowl, and for rare fish species that migrate from the sea to spawn in our rivers,” she said.

“Alternative to a barrage”

The Commission’s report said the UK and Welsh governments should set up an organisation with the private sector to create the lagoon as a “commercial demonstration project”.

It would show the potential for tidal power and measure the impact on the local environment and look at ways to compensate for any loss of habitat, it said.

The report added: “A lagoon project would provide both engineering experience and real-world monitoring of environmental effects. Development of a tidal lagoon therefore offers a positive alternative to a barrage.”

A Severn Estuary Commission/Western Gateway spokesperson added: “The commission has spent the last year engaging with over 500 experts and 200 different organisations across investors, environmentalists, industry and governments.

The Severn Estuary is of environmental importance and the overwhelming view of stakeholders and the latest data show that, after decades of unsuccessful proposals for barrages, lagoons provide a realistic way of harnessing a similar amount of energy with significantly lower environmental impact and at a similar cost.

Although it has been estimated that a large-scale barrage might have the potential to provide 5.2% of the UK’s total energy needs, a project such as the West Somerset Lagoon could provide 2% in its own right, meaning only three lagoons would be needed to create a similar amount of energy.”

“No regrets option”

A decade ago there were proposals to build a lagoon in Swansea Bay. The project, put together by developer Tidal Lagoon (Swansea Bay), was to build the world’s first tidal lagoon power plant. This would span Swansea Bay to form a lagoon between the River Tawe and the River Neath.

Plans were submitted to government in February 2014 and the project received its Development Consent Order (DCO) in June 2015. This backing then needed to achieve a subsidy agreement alongside further environmental permits.

Amid reports of impacts on fish and wider environment, in 2016 Charles Hendry was appointed to lead independent review into £1.3bn lagoon’s viability. A year later the Hendry review backs the lagoon as a “no regrets” option, but the UK government is still to decide its fate.

The plans to build the world’s first tidal power lagoon were thrown out by the UK government in 2018.  Business and Energy Secretary Greg Clark said the £1.3bn project was not value for money, despite claims by developers and £200m in backing from the Welsh Government.

A final blow to the project was dealt by the Court of Appeal, which ruled that in 2022 that work on the project did not commence within five years of receiving planning approval and therefore the DCO is no longer valid.