A Small Scale Wave Energy Convertor System for ocean Wave-based Electrical Power Generation

Abstract

Ocean waves is a viable renewable energy source for Sri Lanka since the island is entirely surrounded by the ocean having almost 20 kW/m energy density. Ocean wave energy is available throughout the year and provides many advantages over many other popular renewable energy sources such as solar and wind. However, only very limited research have been conducted in Sri Lanka on practical systems, which can harness energy from the ocean for power generation. In this background, this research aimed to develop a small scale ocean wave energy convertor (WEC) system applicable to conditions of ocean around Lankan. Accordingly, a small scale ocean wave energy converter system having theoretical capacity of 50 W, based on the heave-type wave energy conversion technology was developed and tested in the ocean bordering Galle. The system composed of a100 l floater attached to a 2.5 m long oscillating structure hinged to a static base having a sprocket and chain driven mechanical system, eventually producing a rotary motion of a flywheel set. The flywheel set carries two large-diameter bicycle wheels to which eight bicycle dynamos having 3 W capacity are attached. As the dynamos rotate, the generated alternating current is sent through a rectifying circuit to produce a 9 V direct current output. The system was tested in the ocean bordering Galle and average power generation was observed to be 8.1 W, resulting in an overall ocean wave energy to electricity conversion efficiency of 30%. Future work of this research will focus more on the improvement of the efficiency and reliability of the system while increasing the generation capacity. The insights drawn from this research will be highly useful in developing much larger scale devices capable of generating electricity from ocean waves around Sri Lanka, providing a sustainable solution to the prevailing local energy crisis.