Fersiwn Gymraeg ar gael yma. 

How best to harness the power of the Severn Estuary is a debate that has been repeatedly revisited over recent decades. Tidal lagoons have been the most recent focus; and much has hinged on the UK Government response to Rt Hon Charles Hendry’s review of the potential of this tidal lagoon technology.

After months of waiting the Westminster Government declared last week that tidal lagoons are not value for money and it will not financially support any of the programme of 6 lagoons promoted by Tidal Lagoon Power (TLP) including Swansea. In many ways, this reinforced the position of the previous Westminster Coalition Government who concluded the 2008-10 review of Severn tidal power by saying that there was no strategic case for government to support a tidal power project and it would not reopen the debate unless or until the strategic context changed (ie if the need grew or the cost of technology reduced). Of course, the debate was then reopened and appears to have been closed again.

The RSPB’s position was to recognise the value of Swansea Lagoon as a potential ‘pathfinder’ to learn more about the environmental impacts of this untried technology – if the outstanding environmental issues, notably the impact on fish, could be resolved.

Welsh Government have taken a far less precautionary approach and signalled their support to the concept of lagoons in Welsh waters. Their draft Marine Plan supports a fleet of tidal lagoons in Wales - but fails to show how this could be achieved in compliance with environmental legislation. We are concerned by this stance, since it is not yet clear that a single smaller scale lagoon (such as Swansea – which yet to secure a Marine Licence) - can be environmentally sustainable.  It also seems inconsistent with the approach in the Hendry Review of learning from a Swansea Lagoon.

Westminster’s decision is an opportunity for Welsh Government to consider the alternative lagoons policy that RSPB proposed in our response to the Marine Plan – one that gives fuller consideration to the environmental risks of tidal lagoon technologies.

Shelduck: one of the species for which the Severn Estuary is designated as a Special Protection Area (Ben Hall, rspb-images.com)

So, what can we learn from the debate this time round?

Once again, missing from the reasons for not proceeding this time is any reference to the environment. We saw tidal lagoon energy as high risk for nature and argued that a precautionary and evidence-based approach was therefore needed. However, this seemed to be overlooked as rhetoric hardened into an all-or-nothing position that pre-judged the outcome of a demonstrator project. So, while we can live with the decision, it is disappointing that the environmental consequences of our energy policy choices don’t get a mention in the reasons for not proceeding.

The RSPB’s 2050 Energy Vision Report published in 2016 shows how a transition to sustainable energy can be made in harmony with nature. This depends on the choice of technologies and on proper consideration of environmental impact in their siting and design. This report found that we can meet our energy and carbon targets with less risk to wildlife and nature than with large scale tidal lagoons. But tidal range energy remains a compelling idea. With partners we published the Severn Vision which includes a goal of developing in harmony with nature, tidal renewable energy. The challenge then is whether there could be a solution that is value for money and environmentally sustainable.

The best places for tidal range energy include some of our most important wildlife sites. The Severn Estuary is not only the location of 4 of the 6 lagoons promoted by TLP, but is also a wildlife wonder. Its mudflat and saltmarsh habitats are natural carbon stores that support over 80,000 wintering waterfowl and wading birds. In its waters are 110 species of fish including seven migratory species which are internationally important not just in the Severn but in the designated rivers that flow into it. That is why we saw a case for Swansea Bay lagoon as a test site, to learn more about the environmental impacts of this untried technology, if - and only if - it was well researched and met environmental standards. At this point in time, we are not satisfied on either of these points.

We also question whether current lagoon technology can be scaled up as envisaged by the Hendry Review while still protecting our marine and coastal wildlife. Evidence shows that a fleet of tidal lagoons will have large scale and complex wildlife impacts. The Welsh Government’s own assessment of a policy supporting multiple tidal lagoons around Wales could not rule out adverse effects on 70+ of the most highly protected wildlife sites (SPA, SAC and Ramsar). This includes sites in all four countries of the UK and some in France and the Republic of Ireland!

There are lessons relevant to the debate about our future relationship with the EU as clearly our wildlife crosses borders and we need co-operative approaches across geo-political boundaries to protect it. We know about these risks because of the environmental assessment that is required by EU legislation, so it is vital to maintain this requirement into the future.

History and experience suggests that tidal range energy will reappear in the political debate again. Much more thinking and research now needs to go into understanding our complex estuary environments and whether tidal energy could be developed in harmony with nature. We were pleased that in 2010 as part of its Severn Tidal Power Study the UK Government published a review of alternative tidal range concepts. One of these concepts has now been developed and adapted into an operational river hydropower scheme. So, if there is a next time, we should start with the premise of finding a solution that not only generates large amounts of renewable energy at a cost that is attractive to the tax-payer but also one that has the least impact on the environment.

A good starting point would be to look again at alternative and emerging technologies.