For the UK it still seems that tidal is the most reliable twice a day solution, but with astronomical lead in costs.They have talked about the Bristol Channel, but nobody has the money or inclination. Solar panels are so inefficient, even though research continues..
Tidal power generation has a number of challenges, primarily cost effectiveness and environmental issues. Our neighbour the Rance tidal barrier was built in 1966 and has had considerable impact on the surrounding area. There is a very good reason why only one other significant barrier has been built in the sixty years since.
