Lily Brennan states that wind power is inefficient and that tidal power is easily available, (News Guardian, September 21).
In fact, wind power is increasingly efficient and economic, though improvements in battery or other storage are still needed.
Tidal power is a huge potential resource, but it’s important to realise that for useful amounts of power a large tidal range is needed (Whitley Bay’s range varies from 1m to 5m), and the engineering work is very large.
A major proposal for Swansea will cost billions, though I believe it’s worth doing.
Dr John Appleby