Select Committee on Science and Technology Appendices to the Minutes of Evidence


Memorandum submitted by Emeritus Professor Keith Clayton, School of Environmental Sciences, University of East Anglia

  1.  The rapid diffusion of wind energy machines in much of Europe and the USA contrasts with the very few—and still essentially experimental—pieces of equipment which utilise wave or tidal flows. Yet the available wave energy which might be exploited is immense, and at least in well-chosen locations, where constriction gives higher velocities in tidal flows, the same is true. The exploitation of tidal flows has the added advantage that even in periods of calm sea, tidal movements continue unabated. Only the long-term shift between Spring and Neap tides limits the extent to which a relatively continuous level of power can be exploited.

  2.  The limited development of wave and tidal power is, in my view, very largely the result of the difficult environment in which such equipment must operate, and the problems involved in making it substantial enough to withstand the worst conditions that can occur. To the extent that this is overcome by robust design, this threatens the requirement to build cheaply enough to make it commercially viable.

  3.  Wave riders of various types can easily be brought ashore for periodic maintenance, even if they will normally be expected to survive the largest waves that occur in the locality they are deployed. Undersea tidal stream devices are expensive to move and secure on site, and hence are more likely to be expected to survive for longer periods without attention. This will usually involve more sophisticated design and probably make them more expensive to build. They are, however, less likely to be damaged during severe storms, provided their anchorage remains secure.

  4.  It seems clear from the very limited progress over several decades that, unless some unforeseen innovation in design occurs, industry is unlikely to regard this energy source as an attractive investment. What has been lacking has been the willingness of government (usually the DTI) to fund the deployment of experimental machines which have been developed and which have passed some type of peer review which regards them as promising (and robust) enough for sea trials. Only by such field trials will the limitations of existing designs be exposed and the experience gained to improve whichever aspects have proved the Achilles heel of any particular machine.

  5.  As a Committee member has suggested, the experience that has been acquired by our offshore oil industry over three decades should find application in particular aspects of this field, especially perhaps the provision of secure anchorages or foundations, and the problems of corrosion by sea water and attrition by moving sediment, as well as the secure placing of power cables to link the offshore generators to the grid. But I remain convinced that however optimistic our designers and engineers may be about new developments, until these have been demonstrated to work and survive for several seasons at sea, the viability of the equipment remains unproven.

25 January 2001

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