In a study published in ACS Nano, a team of researchers led by Zhong Lin Wang at the Georgia Institute of Technology has developed a device that can harvest ocean waves in a very broad frequency range that encompasses almost all of the ocean wave energy spectrum, including the hard-to-reach low frequencies that are inaccessible to most harvesters. The device is a hybrid system that consists of two generators.
An EMG is well-suited for harvesting waves at high frequencies and fast rotation speeds. However, a triboelectric nanogenerator (TENG), which has only recently been investigated for ocean energy applications, works better in the low-frequency range and at slower rotation speeds.
When combined, the two types of generators operate in a broad frequency range and in two modes (fluctuation and rotation), allowing the hybrid device to collect a variety of types of ocean energies, including wave, current, and tidal. Each type of energy causes a different motion that requires a flexible harvesting capability.
The researchers demonstrated the device by using it to light up LEDs that form the words "BLUE ENERGY." The EMG is connected to the word "BLUE" and the TENG is connected to the word "ENERGY" so that the power output of each generator can be viewed individually.
The researchers envision the ocean wave energy harvester as one component of a larger energy harvesting panel floating on the ocean, which could simultaneously harvest wind, solar, and wave energy. They plan to further develop this concept in the future.