Tidal Lagoon at Swansea Bay


A review of the future role of tidal lagoons in the UK has strongly backed a prototype lagoon in Swansea Bay. Former Energy Minister Charles Hendry led the review, which included evidence from 200 parties and forms a basis for government decision-making.

The Swansea Bay project was awarded a Consent Order in 2015, and onsite construction is primed to commence in 2018. It will comprise 16 hydro turbines and a six-mile breakwater wall, generating electricity for 155,000 homes. A government decision is expected in the next few months.

A tidal lagoon is a U-shaped breakwater that contains a bank of hydro turbines. Water enters and leaves the lagoon with the tides so that power is generated four times a day. The UK is a beneficial location as it has the second highest tidal range (the difference between high tide and low tide) in the world, and at Swansea Bay, the difference can be as high as nine metres.

Charles Hendry’s supportive report considered areas such as security of supply, value for money, and environmental impact. Tidal lagoons provide a secure supply because of the indigenous nature of the fuel and the predictability of the output. They also have greater longevity than other renewable technologies, of 120 years or longer.  While this is advantageous, it creates a challenge for making cost comparisons with other technologies that have operating lives of 25 to 60 years. The report asks whether the best approach would be for energy consumers to pay for tidal lagoon projects within a short timeframe or whether a longer timeframe would achieve the best value for consumers.

Critics raising concerns regarding the £1.3 billion prototype suggest it would be better to wait for improvements in the technology or for the cost of wind and solar to fall further and to make more use of those technologies. However, economies of scale could be achieved if the prototype leads to investment in several lagoons around the UK. The government would be required to give investors assurance of any support measure given its track record of cancelling schemes at short notice.

The development of tidal lagoons is important to both the local and national economies and provides an opportunity for the UK to be a technological innovator and develop lagoons overseas.

Nikki Wilson

Nikki joined Alfa Energy in September 2015 as a Carbon Management Consultant where she advises clients on legislation, compliance, and the implementation of carbon management schemes. She is a Practitioner member of IEMA, has a postgraduate diploma in Environmental Decision Making, and has over 15 years’ experience in energy consultancy.