This Commons Library briefing provides an overview of the potential UK wave and tidal resource and the Swansea Bay Tidal Lagoon project.Jump to full report >>
Around half of Europe’s potential wave and tidal resource is thought to be in the UK. It has been estimated that this resource could help to meet up to 20% of the UK’s current electricity demand. No large scale tidal lagoons have been developed in the UK. Tidal Lagoon Power (TLP) wanted to acquire the necessary permissions for a ‘pathfinder’ project in Swansea Bay.
UK tidal energy resources
The UK is estimated to have around half of the potential wave and tidal resource in Europe. Tidal power availability is very site-specific; the highest tidal ranges in the UK are on the west coasts of England and Wales, in the Bristol Channel and Severn Estuary. Scotland has a smaller tidal potential, but offers the majority of the UK’s wave resource.
There have been suggestions of a tidal barrage in the Severn Estuary (the second highest tidal range in the world) for many years. Projects for tidal lagoons in the UK are a more recent development. Some view tidal lagoons as a more economical, technically feasible and environment-friendly alternative to tidal barrages, though this view is not universal.
Swansea Bay Tidal Lagoon
Tidal Lagoon Power (TLP) hope to construct a man-made, 320MW (megawatt) tidal Lagoon in Swansea bay, averaging 14 hours of generation every day. The lagoon would have 16 hydro turbines and a six mile breakwater wall. TLP estimated it could generate electricity for 155,000 homes for 120 years.
Owing to cost concerns, the Government commissioned former Energy Minister Charles Hendry to review the project. The Hendry Review (published in January 2017) supported the idea of a Swansea tidal lagoon as a small pathfinder project before large-scale lagoons are rolled out. The Welsh First Minister has urged the UK Government support the project.
The potential benefits and challenges of Swansea Bay Tidal Lagoon
Advocates of the project argue that the Swansea tidal lagoon would benefit the Swansea area economically and contribute to meeting the UK’s need for affordable low-carbon energy. Research by TLP found that a programme of lagoons could generate 30 TWh of electricity per year for 120 years (a lagoon’s lifespan).
Opinions are divided on the value for money of the Swansea tidal lagoon project. The strike price and generation costs have both been cited as key challenges to the deployment of tidal lagoons in the UK. A number of different strike prices had been reported, most recently in it was reported in February 2018 that as a result of discussions between TLP, the UK and the Welsh Government, TLP made a new offer on strike prices on the same terms as the Hinkley nuclear power station (92.50 per MW for 35 years).
On 25 June 2018, the Secretary of State Greg Clark made a statement to Parliament on the Swansea Tidal Lagoon, saying the project did not offer value for money and the Government would not be entering into a contract with TLP.
 By ‘a Programme’ TLP mean the Swansea Lagoon plus 5 full scale lagoons.
 Stefan Messenger, Tidal Lagoon ‘has offered Government new deal on price’, BBC, 22 February 2018
Commons Briefing papers CBP-7940
Authors: Suzanna Hinson; Jeanne Delebarre; David Hirst