Wave Energy Study: Nel Oscillating Water Column (Wave Piston) Bottom Standing Device, Updated Interim Study

Abstract

During the development of the second Interim Reference Design for the National Engineering Laboratory Oscillating Water Column Wave Energy Device (reference 1) it became apparent that there would be considerable problems associated with the moorings and power transmission riser. It was seen that these areas represented approximately 21% of the capital cost and 18% of the continuing maintenance cost of the floating device. These costs could be avoided by a bottom standing structure. Accordingly this feasibility study was initiated by NEL to establish the basic concept for a bottom standing oscillating water column. It was assumed that the device would be situated off the west coast of the Outer Hebrides. On the basis of the study carried out for the floating units two principal design criteria were identified. 1. As little construction work as possible should be performed at the offshore site location. 2. The amount of structure required to resist long term hydrostatic pressures should be minimised.