OPINION LETTERS

摘要

Hans van Haren correctly points out that tidal flow is not likely to meet all our energy needs, but his suggestion that it is therefore not worth trying to exploit this energy source is wrong (3 April, p 20).rnNo single resource can ever provide all our energy. "Only" 20 per cent of our electricity needs would be a very substantial contribution to replacing fossil fuel, equivalent to the world's installed hydroelectric capacity.