The government has turned down the Swansea tidal power lagoon, purely on the basis that it costs too much. On the other hand, maybe they read this week's New Scientist, which concludes the maths and ecology don't stack up. Perhaps the right decision, for different reasons? https://www.newscientist.com/article/mg23831832-700-why-tidal-power-wont-solve-the-worlds-renewable-energy-needs/ (paywall)