Several letters on renewable energy have made the point that wind is not reliable, but then include tidal energy schemes in the same breath.
We have 24-hour tidal energy available around the British coastline.
A large number of (small, simple) machines in suitable positions could produce continuous power several times greater than that intermittently produced by the Severn barrage.
Richard Buchanan
London
Nanogenerator consumes CO2 to generate electricity
Nice to see my my views being backed up by no less a figure than Sabine Hossenfelder https://youtu.be/QoJzs4fA4fo