Modified Floater of Heaving Device Wave Energy Converter (WEC): An Experimental and Numerical Study

Indonesia has a population nearing 300 million and an electricity consumption of 1,285 kWh per capita. However, Mentawai Waters which is surrounded by wave energy potential, still has 23 out of 43 villages off-grid. This study examines energy extraction in Mentawai Waters using a Wave Energy Converter (WEC) with a heaving device mechanism. It focuses on measuring heaving motion, and excitation force, and calculating power and energy production. The heaving WEC device type is selected for its suitability with the local environmental characteristics. The most important of which are wave heights reaching 2.3 m and periods reaching 8.3 s. A combination of experimental testing using the Towing Tank Laboratory and numerical methods with the Boundary Element Method (BEM) is used to optimize the results. The tests focus on six variations of floater diameters ranging from 23 to 33 cm, under wave heights of 0.04 to 0.08 m, with wave periods ranging from 0.6 s to 2.6 s. Both methods indicate that the 29 cm diameter (Floater Type 2) is the most optimal variation, with an average mechanical power output of 446 watts, which is 26.17% higher than Floater Type 1. At a 1:1 scale, an array of 10 Floater Type 2 WECs, with a maximum annual energy output of 35,226 kWh, confirms the point absorber as a suitable WEC type for Mentawai Waters, capable of illuminating key areas, including public facilities.