The Oscillating Wave Surge Converter

The Oscillating Wave Surge Converter (OWSC) is a novel shoreline or near-shore wave energy converter. The concept has developed from an analysis of the performance of the LIMPET shoreline oscillating water column. This analysis showed that the hydrodynamics of shoreline wave energy converters are highly non-linear and that they have a qualitatively different response to similar devices that are sited in deeper water. In particular, the water particle motion in shallow water is predominantly horizontal, with elongated wave troughs and heightened wave peaks. The OWSC is designed to couple strongly with the horizontal particle motion, permitting large amplitudes of motion of the working surface whilst minimising energy losses in associated water particle motions. The OWSC consists of a paddle rotating about a horizontal axis above the water surface and perpendicular to the direction of wave propagation. The paddle hangs at the mouth of a gully, effectively forming a ‘water column’ between the paddle and gully back wall. Thus, the OWSC is similar to the Japanese ‘Pendulor’ system; however the OWSC uses resonance of the water column rather than harbour resonance as its operating principle. A limited study of geometric parameters using a two-dimensional wave-tank model has been performed. Results from these experiments have shown that the ‘water column’ has an effect on the paddle dynamics and OWSC performance, with the OWSC having a higher power capture than both a shoreline oscillating water column (OWC) and Pendulor in shallow water. The potential for the OWSC in the shoreline and near-shore regions is also discussed, with implications for construction costs and the price for electricity generated by the OWSC. Potential control strategies for the OWSC are also discussed, together with their likely effect on operation and performance.