Swansea Bay on the west coast of England is one of the few places in the world where the difference between high and low tide is so extreme. The tidal range of eight to ten metres makes the bay an ideal location for a tidal lagoon. The planned breakwater in the bay will be about fifty to one hundred metres wide and almost 10 kilometres long. There will be 16 turbines that can supply 320 MW, making this the world's largest tidal lagoon and delivering sustainable energy to 155,000 households.
Deltares tested the design for the lagoon using a scale model. Researchers looked at how they could prevent unnecessary energy losses as water flows in and out, the aim being to make the plant as efficient as possible. Dedicated flow models were used. The study showed that the inflow to the turbines was suboptimal and so improvements should be made. The knowledge acquired can also be used on other projects for tidal power plants, such as the EU project Energising Deltas, which was completed in 2015 and looked at the optimisation of energy production and the minimisation of the impact on the environment.