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Abstract This work aims to get a better insight into the behaviour of CECO, an oscillating-body wave energy converter that presents a singular feature: the motion of its oscillating part is restricted to translations along an inclined axis. In order to study in the time domain the response of CECO for a wide range of wave conditions, a hybrid numerical approach based on the Boundary Element Method (BEM) and the Morison’s equation was used. The effects of the power take-off system were included in the numerical model and calibrated with the results from previous wave basin experiments. The results show that CECO is able to capture up to 40% of the incident wave energy when the direction of translation is 45°. However, if the direction of translation is vertical, the amount of captured wave energy decreases almost three times. This investigation demonstrates the advantage of limiting the oscillation of the CECO floating part to an inclined direction and reaffirms the concept as a promising technology for wave energy conversion.

Abstract This work investigates the performance of CECO, a third-generation wave energy converter of the oscillating bodies group. The power matrices of the device – which represent the wave power absorbed for different sea states – are obtained for five PTO inclinations. Then, the wave climate along the west coast of the Iberian Peninsula is characterized by means of the wave energy resource matrices. With the power matrices and the wave energy resource matrices, the performance of the device along the area of study is determined for each PTO inclination. To achieve this, the performance of CECO is assessed by means of a panel model based on the boundary element method, while the wave conditions in the area of study are assessed with a wave propagation spectral model. The results allow fulfilling an important knowledge gap concerning the impact of the PTO inclination on the performance of CECO, which was found to be very significant. In addition, the insight obtained will contribute to optimize future versions of CECO and other wave energy converters of the oscillating body type.

Abstract CECO is a recently proposed Wave Energy Converter (WEC), which harnesses both the kinetic and potential energy of waves. Currently, CECO is at the third level of technology readiness (TRL3). In this context, maximising the wave energy absorption under a wide range of wave conditions is crucial for the future development of the device. Therefore, this work aims to explore in detail the main parameters (operating water depth and wave conditions) that influence CECO's performance in terms of Captured Energy ( C E ) and Captured Energy Efficiency ( C E E f f ). For this purpose, a panel-based model, which was calibrated from previous physical model tests was used to construct the CECO matrices of absorbed wave power at different operating water depths. The wave conditions of the Atlantic coast of the Iberian Peninsula (2005–2014), which were modelled using SWAN, were used as case study. Overall, CECO offers promising results for C E and C E E f f , reaching values up to 600 M W h and 45%, respectively. In addition, it was found that CECO's power absorption reaches its maximum for values of peak wave periods ( T p ) ranging from 10 to 13 s and the fact that the operating water depth does not impact significantly the performance of the device.

CECO is a novel Wave Energy Converter (WEC) concept, which has shown promising results in previous studies. The present work focuses on assessing the performance of CECO for a 11-year horizon in relation to the characteristics of the wave climate (intra and inter-annual seasonal variations) by means of two performance indicators defined ad hoc: Captured Energy (CE) and Captured Energy Efficiency (CEEff). For this purpose, the CECO matrix of absorbed wave power was constructed for an operating water depth of 30 m using the panel-based model ANSYS®-AQWA™. The Atlantic coast of the Iberian Peninsula, which presents a highly seasonal and energetic wave climate, was used as case study. Overall, it was found that CECO is able to capture large amounts of wave energy, especially for milder wave conditions, with values of CEEff exceeding 40%. However, for harsher wave conditions the results of CEEff decrease considerably ranging from 10% to 20%, which may result from the current design of CECO. In this context, the results obtained offer some valuable insight into the future evolution of CECO with the purpose of addressing the limitations of the current design and to optimise its performance according to the wave conditions for specific locations.

Previous experimental works proved the ability of CECO to harness wave energy. This wave energy converter (WEC) is presently at Technology Readiness Level (TRL) three, where characterizing the energy conversion stages and evaluating the energy conversion efficiency is crucial. Therefore, in this work Ansys® Aqwa™ was applied to study a CECO unit and to obtain a detailed knowledge of its performance throughout the different energy conversion stages. The numerical model was initially calibrated with results from experimental tests and then used to simulate different configurations of the power take-off (PTO) system under a wide range of regular and irregular wave conditions. For most of the irregular wave conditions tested, CECO can absorb between 10 and 40% of the incident wave power and transmit to the electric generator up to 18%. Although the results reveal a high energy conversion efficiency, there is still scope for improvement of the device by optimizing the PTO. On these grounds, the ideal values of the electric generator damping coefficient are presented for different wave conditions, which allow to define an adequate control strategy in future works.