Recovery Act - Variable-Geometry Oscillating Wave Surge Converter for Utility-Scale Electricity Production

Oscillating Wave Surge Converters (OWSC) have shown great promise as a cost-effective means of harnessing the power of ocean waves yet little is known about the effects of different paddle geometries on critical performance factors including power production, survivability, and ecological impact. As a consequence, widespread commercialization of OWSC technologies will be delayed until such information is well understood. The overall objective of this project is to develop an OWSC that, through dynamic shape-adjustment of its energy-absorbing paddle, can maximize power production across a broad range of wave conditions and, when necessary, shed excessive energy when extreme loads are encountered so as to improve device endurance and safety while minimizing environmental disturbances. In Phase 1 we began the process of gathering needed information by developing a numerical modeling tool for predicting the response of various OWSC paddle configurations in different wave conditions. We then proceeded to conduct a total of 960 wave tank experiments using fifteen different paddle geometries to validate the tool and determine performance end-points, i.e., most responsive/least responsive paddle shape. At the conclusion of Phase 1 we were able to verify the effectiveness of varying paddle volume as a means of modulating power generation and as a means of minimizing exposure to destructive forces while, at the same time, maximizing the effectiveness of a power take-off (PTO) system. In Phase 2 our plan is to: a) improve our numerical analysis capabilities by building a time-domain, panelmethod tool for use in further design/analysis work; b) develop and test a means for our OWSC to dynamically transition between most responsive and least responsive paddle shapes; c) incorporate a PTO system which transforms mechanical power provided by the paddle: (i) into working-fluid flow; and (ii) directly into electricity; and d) conduct further wave tank and ocean tests to verify performance and finalize the design that will be commercialized in Phase 3. Commercial Applications and Other Benefits: In Phase 3, we will be prepared to immediately commercialize our OWSC device into a specific target market where we have already identified a pilot customer. The public benefits will include: a) the establishment of performance, integrity and safety values for OWSC paddles across normal, severe and extreme operating conditions; and b) materials cost and quality benchmarks against which further improvements can be made; leading to; c) more-rapid commercialization of a technology that will reduce U.S. dependence on foreign energy resources, speed compliance with renewable electricity standards (RES), and reduce risks associated with climate change.