Q7Power Generation Sources

Ocean waves are generated by wind blowing over long stretches of open water (fetch), transferring energy to the water surface in the form of both kinetic energy (orbital motion of water particles) and potential energy (elevation of water above the mean sea level). The energy density of ocean waves is quite high, and wave energy converters (WECs) are devices designed to capture this energy and convert it into electricity.

Common wave energy conversion technologies include: (1) Oscillating Water Column (OWC) devices — a partially submerged chamber open below the water line traps air above the water surface; as waves rise and fall, the trapped air is alternately compressed and drawn through a Wells turbine (which rotates in the same direction regardless of airflow direction), driving a generator; (2) Point absorbers — small floating buoys that move up and down (heave motion) relative to a fixed sea-bed reference, this relative motion driving a hydraulic pump or linear generator; (3) Attenuators — long, multi-segment floating structures oriented parallel to wave direction, where the relative flexing motion between segments at hinged joints drives hydraulic rams; (4) Overtopping devices — a ramp structure captures water from incoming waves into an elevated reservoir, which is then released through low-head turbines, similar in principle to a mini hydroelectric scheme.

Wave energy is abundant along coastlines with strong, consistent wave climates and offers the advantage of relatively high energy density and predictability compared to wind, though the technology faces challenges of high capital and maintenance cost, survivability in storms, and corrosion in the harsh marine environment, limiting it currently to demonstration and pilot-scale deployment worldwide.