Virginia Tech researcher, in collaboration with wave energy company and research laboratories, is working on the new power take-off (PTO) solution for wave energy converters in an effort to improve energy conversion efficiency and the reliability of ocean wave energy harvesting.
The collaborative initiative, pushed forward by the US Department of Energy’s (DoE) $2 million grant awarded in August 2015, is developing the Mechanical Motion Rectifier, a novel power take-off that uses the up and down and back and forth oscillation of wave energy and turns it into a unidirectional rotation to drive the generator.
Lei Zuo, Associate Professor of Mechanical Engineering at Virginia Tech, has teamed up with researchers from the National Renewable Energy Laboratory (NREL), Resolute Marine Energy, and THK North America to design, build and test a 500-watt unit using ball screw and Mechanical Motion Rectifier mechanism, which will be followed by the construction of a 10 kW device housed in a container about 5 meters in diameter, that is ultimately expected to result in a full-sized wave energy converter that can be scaled up to about 25 meters in diameter, able to generate about 0.5 MW of power.
Energy generation begins almost immediately as the waves move the buoy and the components inside, according to Virginia Tech.
In addition to constructing the novel wave energy device, Zuo’s team must achieve minimum gains of 50% in reliability and 25% in power output, lowering the cost per unit of energy as part of the DoE grant conditions.
So far, the team has built a small, 1.2-meter proof-of-concept device using rack pinion, which was tested off the coast of Long Island, but the researchers hope to deploy a 500-watt unit by the end of the year.
Lei Zuo said: “Our expectation is that by summer we’ll have tested the components of the smaller device in lab, and we will then put the 500 W wave energy converter in the water off Hampton Roads, Virginia, by November. The data we collect there will help us make improvements to the larger unit which will be tested, probably in Hawaii at the Navy’s Wave Energy Test Site, in 2017.”
In a 2010 estimate, the energy potential from ocean waves could make up 64% of the electricity generated from all sources of energy in the United States.