Numerical analysis of the energy capture performance of a six-leg wave energy converter under Mexican waters wave conditions

Abstract

Wave energy converters (WECs) with multiple degrees of freedom based on the concept of parallel manipulators are promising devices to increase power generation. In recently published research, WECs based on parallel mechanisms were studied and showed higher output power than traditional devices. Therefore, this paper introduces the concept of the six-leg WEC and compares its performance against the single-leg and the three-leg WECs, considering they are floating devices with each leg represented by linear electrical generators. A time-domain model is developed for each device to investigate their power output in irregular waves. The annual energy production (AEP) and some indirect cost-related performance measures are assessed at four sea sites in Mexican waters, at which the mean level of wave power resource ranges between 10 and 25 kW per meter of wave-front. The results show that when compared with the single-leg and the three-leg devices, the six-leg WEC: (i) has higher values of AEP, (ii) exhibits lower performance measures, (iii) has the highest cost of energy, and (iv) could have smaller capacity electrical generators. The overall conclusion is that the power take-off machinery connected to each leg should have different capacities depending on the number of legs used.