Experimental Performance Analysis of a Hybrid Wave Energy Harvesting System Combining E-Motions with Triboelectric Nanogenerators

• Published in: Journal of marine science and engineering Vol. 10; no. 12; p. 1924
• Main Authors: Clemente, Daniel, Rodrigues, Cátia, Esteves, Ricardo, Correia, José, Pereira, André M., Ventura, João O., Rosa-Santos, Paulo, Taveira-Pinto, Francisco, Martins, Paulo
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-12-2022
• Subjects: Adaptability; Alternative energy sources; Analysis; Ballast; Case studies; Damping; E-Motions; Electric generators; Electric power production; Electricity; Energy conversion; Energy harvesting; Energy industry; Energy resources; Hybrid systems; Hybridization; hydrodynamic response; Hydrodynamics; Maximum power; Nanogenerators; Open circuit voltage; Oscillations; physical modelling; Roll response; Technology; triboelectric nanogenerators; Wave energy; wave energy conversion; Wave excitation; Wave power; Portugal
• ISSN: 2077-1312; 2077-1312
• DOI: 10.3390/jmse10121924

This paper discusses a disruptive approach to wave energy conversion, based on a hybrid solution: the E-Motions wave energy converter with integrated triboelectric nanogenerators. To demonstrate it, a physical modelling study was carried out with nine E-Motions sub-variants, which were based on three original hull designs (half-cylinder (HC), half-sphere (HS) and trapezoidal prism (TP)). A unidirectional lateral tribo-device was incorporated within the E-Motions’ hull during the experiments. The physical models were subjected to eight irregular sea-states from a reference study on the Portuguese coastline. Results point towards a significant hydrodynamic roll response, with peaks of up to 40 °/m. Three peaks were observed for the surge motions, associated with slow drifting at low frequencies. The response bandwidth of the HC sub-variants was affected by the varying PTO mass-damping values. By comparison, such response was generally maintained for all HS sub-variants and improved for the TP sub-variants, due to ballast positioning adjustments. Maximum power ratios ranged between 0.015 kW/m3 and 0.030 kW/m3. The TENGs demonstrated an average open-circuit voltage and power per kilogram ratio of up to 85 V and 18 mW/kg, respectively, whilst exhibiting an evolution highly dependent upon wave excitation, surge excursions and roll oscillations. Thus, TENGs enable redundant dual-mode wave energy conversion alongside E-Motions, which can power supporting equipment with negligible influence on platform hydrodynamics.