We are delighted that you have at last given the capture of tidal power the prominence that it deserves by placing it on the cover (NCE 19 September).
Stingray - which employs tidal rather than wave energy as you suggest - is an interesting and original idea and worth the cost of a prototyping exercise.
Several groups around the world are exploring the capture of the kinetic energy of the tides, for example, the Dalupiri Project in the Philippines uses Davis turbines with a tidal power fence and will generate on average 1100 MW, about as much as a nuclear power station like Sizewell.
We have recently completed a design for an accelerating tidal power barrier on the Mersey at Liverpool which is one of the best locations for a tidal power barrier in the UK.
We too think tidal power barrages are not the way forward: our proposed barriers use the really simple Davis turbine design combined with a minimum energy loss transition to accelerate the natural tidal stream and minimise the head drop across the structure.
We remain convinced that tidal power is the best of all energy resources and Britain is wonderfully well endowed with this valuable resource.
Dr John Loveless, Prof Roy Severn, Dr David Bickley, Faculty of Engineering, University of Bristol.