The potential of extracting wave energy from rip currents
Existing wave energy converters are only based on a few ways to produce electricity from ocean waves. All of them suffer from low cost-efficiency so the proposal of new technologies is still up to date.
This is a preliminary study to an innovative concept, based on wave-induced currents. As waves propagate into shallow water and break over a barrier, they dissipate their energy. The latter can be partly transformed in a hydraulic potential through the wave set-up behind the barrier and the cross-shore mass transport from waves. Electricity can then be produced by the mean of a water turbine.
This study estimates qualitatively this energy potential. The 2D set-up is analyzed by the model of Calabrese et al. (2008) and is adapted to 3D for a regulated net cross-shore discharge. The 3D model of Bellotti (2004) is also used. Experiments have been carried out on a simplified lab-scale model to check qualitatively the applicability of the models, determine experimentally their calibration parameters and find the optimal combination flow rate/pressure head which gives the highest hydraulic potential. Two different barrier profiles are tested: a breakwater-like barrier with a steep seaward slope and a sandbar-like barrier with a mild slope. Despite a significant uncertainty, experimental and analytical results correlate well.
The conclusions on the future of this technology are not thorough. Experimental conditions applied to full scale show a quite low efficiency compared to the main competitors, but much more perspectives of optimization are conceivable. Some of them have been studied from an analytical point of view.
Place, publisher, year, edition, pages
Institutt for energi- og prosessteknikk , 2011. , 103 p.
ntnudaim:6411, MTPROD produktutvikling og produksjon, Energi-, prosess- og strømningsteknikk
IdentifiersURN: urn:nbn:no:ntnu:diva-12993Local ID: ntnudaim:6411OAI: oai:DiVA.org:ntnu-12993DiVA: diva2:429671
Ytrehus, Tor, Professor