Necessity is the Mother of invention

Misunderstanding of the nature of wave, tide and wind power masks the radically different potential of wave power

The article on the Pelamis Wave Power project (PE March 2012) is most welcome and not before time. It is extraordinary that such a source of power is today so misunderstood that it needs Richard Yemm, the author, to point out that the world’s oceans are the huge reservoirs of energy that they are. Long-standing and ongoing misunderstanding of the nature of wave, tide and wind power masks the radically different potential of wave power. Even the title chosen by the PE Editor confuses by mentioning tide.

The kinetic energy of the complex rotational water motion within long fetch oceanic rollers is where this very special energy lies; the means of tapping it efficiently needs a special device such as Pelamis or other solutions variously embryonic or under development. Here is a major challenge for mechanical engineers but our collective response is so far hardly impressive; however this author is doing well as something of a lone voice in the eco-babble. Indeed he relates he is risking his own career and assets to sustain progress, which is a scandal considering the sums available for other renewables. Meanwhile we spend many millions on sea wall defences to fend off that same energy threatening our coastline.

It seems to me we are currently not far out from the starting gate. Viewed theoretically wave energy within a volume of water is quantifiable. Supposing an efficient conversion into mechanical power were to be possible, quantifiably less energy downstream and the resulting calmer waters can be imagined. The medium possessed of the energy transmits it without travelling itself, a very important difference when compared with wind and tide – each has its problems and advantages but scaled down research of wave power converters assuring backers of full scale performance is very problematic. Those working in the field can better explain the complexities but I wager that 10 years from now wave power will be favoured over both wind and tide, simply because the energy is there and sites that upset no-one do abound; there are quite as many sites as we need in our northern waters alone. And necessity is the Mother of invention.

Designs and project ideas for converters that would be more efficient than Pelamis do exist. Doubters prevail however, inter alia scaling up problems and fear of storm wipe-out and then lack of funding seriously inhibit progress. Unfortunately reigning gurus such as Professor David MacKay, a physicist (see www.withouthotair.com), and others, have ruled out any imagined man-made calming of the waters around our coast for the present and continue to give a bad press. Re-aligning their logic or lack of it along sound engineering lines is a vital task for all of us. Pelamis deserves stronger endorsement as do competitive projects.

Roger Harris

Next letter: Acknowledging mistakes