Supplementary Report On The Feasibility Study Of Submerged Cylinder Wave Energy Device

Abstract

This report has been compiled as the result o f a four-month supplementary contract to our first broad look at submerged cylinder wave energy devices. In this further period we have discussed widely within the wave energy community the findings of our main Report dated October 1979. We have also considered topics that were either not within our earlier brief or were only peripheral to its principal purpose of identifying how the device could be engineered using proven technology, and the likely range of unit costs that this could involve. The present Report therefore covers a wide spectrum of topics. These are mostly pitched in the form of 'Appe ndix' notes to subjects studied and presented in our main Report. They serve to clarify points of detail, and have been pursued in sufficient depth to show whether they need be studied further in the next phase of this enquiry. We have also continued our studies of the main subjects underlying the behaviour and performance of the device, especially its dyna mic behaviour in response to wave motion and how energy is best transmitted to and through the seabed power takeoff units. This supplementary period has therefore allowed us to narrow our options, Although we believe it is still premature to expect the preferred system of mooring and power takeoff to be selected with certainty, our earlier recommendations are upheld by the further findings now presented. This system will therefore form the basis for the optimisation study of the device that now logically follows, but we will continue to seek improvements both to the overall arrangement of the device and to its component parts in the light of all further information that becomes available to us. We conclude that the submerged cylinder device is a technically sound and efficient way of capturing wave energy. On the basis of present knowledge we have reason to believe that, from the thorough optimisation study that constitutes the next phase of our work, the device may also turn out to be an economic proposition. In this case it should be advanced through a full engineering design phase to the prototype construction of perhaps five units at full scale in say 1984/5