Physics World March 3, 2020
Most approaches to harvesting mechanical energy from ocean waves rely on finding a way to move a conducting wire through a magnetic field to generate electricity. Researchers at Georgia Institute of Technology designed triboelectric nanogenerators (TENGs) in small plastic spheres, about the size of oranges, that float in water. As the waves jostle the sphere, material inside bumps against the outer shell, generating charges. Th charges then flow through an attached wire. In lab tests each sphere could generate about 10 mW of power enough for powering small devices such as sensors on buoys used to collect data on the sea. TENGs follow the rules of electrostatic generators, which means that their output scales linearly with frequency. While conventional wave harvesters have an advantage for giant swells, TENGs can function even with small vibrations. Rivers, which typically don’t have a strong enough current for wave harvesters, might therefore be good testing grounds for TENGs…read more.
Blue dreams: Artist’s impression of AW-Energy’s WaveRoller – a device that is undergoing testing off the coast of Portugal. (Courtesy: AW-Energy Oy)