Energy Harvesting and Storage System Stabilized Offshore Wind Turbines

Abstract

This paper investigates the potential for combining energy harvesting and damping systems as a means for stabilizing floating offshore wind turbines while increasing the total amount of power generated. Ever taller wind turbine towers are needed to accommodate ever larger rotor diameters, which for floating offshore turbines would normally necessitate ever deeper draft marine structures, such as spar buoys, to provide required stability. Damping structures, some of which have energy harvesting mechanisms, have been proposed and shown to be effective for floating turbines, but face the problem of transforming low frequency variable amplitude motion into steady power output. Here the idea of a piston pump in the form of a moving float mechanism is introduced to pump water out of a temporary storage chamber located at the bottom of a floating platform structure. Water flowing down the floating structure through a power turbine empties into the chamber. The entire structure might ideally now only depend on a single anchor line projecting from its center bottom to the seafloor, thereby also reducing the cost of moorings.