Sea motion electrical energy generator for low-power applications

The main problematic about electronic systems deployed in the sea for long periods of time, is to find a feasible way to supply them with the necessary amount of power and no direct supervision. In this paper a new idea is proposed and studied to supply deep sea low-consumption devices using low-cost disk piezoelectric elements. These piezoelectric components, together with a horizontal balance-like physical pendulum, create an electrical power generator that harvests the mechanical energy brought by the sea movements, preferably from the heave and pitch motion that sea waves induce in a moored-floating body as might be a buoy. The main purpose of this system is to unrelate the rate of impacts to the piezoelectric material from its natural oscillation frequency, making it viable to harvest energy from a slow motion environment such as the sea. Equations relating the energy extraction are presented and different experimentations are worked out to characterize the piezo elements. Finally a prototype with a proposed electronic harvesting system is built and tested in a real medium, showing the results before concluding the article.