Piezoelectric Artificial Kelp for Energy Harvesting

This study focuses on a hydrokinetic energy harvesting system concept using piezoelectric materials. The Piezoelectric Active Kelp (PAK) system will consist of chemically inert piezoelectric polymers or piezoelectric ceramics manufactured into long flexible ribbons. The PAK system will convert the natural mechanical motions seen in kelp forests due to oceanic wave action, into electricity. As the periodic ocean currents, resulting from waves, pass over the PAK system, they cause the structure to oscillate back and forth. The piezoelectric materials will convert this mechanical motion directly into electrical power via the inverse piezoelectric effect. Large numbers of piezo-kelp ribbons would be mounted like forests on the ocean floor, producing a constant stream of smart grid power. PAK forest systems would also provide an artificial marine habitat while meeting the world’s demand for inexpensive and sustainable energy. Contrary to most forms of hydrokinetic energy harvesting system, the PAK system has no fast-moving parts or turbines and will be made of environmentally inert materials. The amount of power harvested by the PAK system depends upon the flow conditions, device configuration and size, and its piezoelectric material properties. Assuming specific flow conditions and fluid-structure interaction, this study will determine the optimal piezoelectric material to use, along with physical dimensions and layup configuration, to maximize the volumetric power density of the PAK system. The power generated by three common piezoelectric energy harvesting configurations: the unimorph, a homogeneous bimorph and a heterogeneous bimorph, will be compared for both a piezopolymer and a piezoceramic. Additionally, an appropriate figure-of-merit is also identified, based on the piezoelectric coefficient product (d₃₁· g₃₁) to compare the power production capabilities across materials.