Point Absorber Wave Energy Harvesters: A Review of Recent Developments

Abstract

Even though ocean waves around the world are known to contain high and dense amounts of energy, wave energy harvesters are still not as mature as other forms of renewable energy harvesting devices, especially when it comes to commercialization, mass production, and grid integration, but with the recent studies and optimizations, the point absorber wave energy harvester might be a potential candidate to stand out as the best solution to harvest energy from highly energetic locations around the world’s oceans. This paper presents an extensive literature review on point absorber wave energy harvesters and covers their recent theoretical and experimental development. The paper focuses on three main parts: One-body point absorbers, two-body point absorbers, and power take-offs. This review showcases the high amount of work being done to push point absorbers towards technological maturity to eventually kick off commercialization and mass production. It should also provide a good background on the recent status of point absorber development for researchers in the field.

Wave flume testing of an oscillating-body wave energy converter with a tuned inerter

“…Unfortunately, considerable discrepancies are observed especially in the TI WEC, i.e., Type B1, B2, and B3 and these results imply the difficulty of developing accurate analytical models of the 2DOF smallscale prototype under external loadings of various frequencies. The possible causes of these discrepancies are that (1) the conditions for Airy linear wave or Stokes first-order theory assumed in the WAMIT [31,33] are not satisfied in the wave flume testing [34]; (2) the drag force which might not be negligible around the natural frequency of the buoy, i.e., 0.8 s or 0.9 s, is ignored in the simulation [35]; (3) all the mechanical energy losses including the friction losses in the prototype and the nonlinear hysteresis damping by the constantforce spring are modeled by constant viscous damping coefficients [35]; and (4) waves reflected from side walls which act on the buoy are not considered in the simulation studies. However, these are common problems seen in experiments using small-scale models, which are difficult to address.…”

Multi-DOF WEC Performance in Variable Bathymetry Regions Using a Hybrid 3D BEM and Optimization

“…The result will be used, in normalized form with respect to incident power, to quantify the overall performance of the WEC and will be called performance index (PI%).  [1,5,10,20,40,80, 100].…”

“…Renewable energy from the oceans is increasingly attracting the interest of the scientific and industrial society. Wave energy converters are constantly being deployed in areas characterized by increased potential, and a recent review concerning point absorber wave energy harvesters is presented in [1]. The performance of the devices installed in the nearshore and coastal environment, where the bottom terrain may present significant variations, can be evaluated by formulating and solving interaction problems of free surface gravity waves, floating bodies, and the seafloor; see, e.g., Wehausen [2] and Mei [3].…”

Wave-to-Wire Power Maximization Control for All-Electric Wave Energy Converters with Non-Ideal Power Take-Off

“…The EMF of the generator is produced by implementing (3). N t is the number of turns around a tooth, Φ is the flux in the tooth and τ p is the pole pitch.…”

“…In this research paper, the focus is given to modelling single-body point absorber WECs with all-electric PTO. Single-body absorbers are chosen because they are more mature, can be designed more easily to suit a specific sea state, and a large number of demonstration projects have been implemented [3]. The use of an all-electric PTO is crucial for the final goal of this research.…”