Development of an alternating lift converter utilizing flow-induced oscillations to harness horizontal hydrokinetic energy.

The Vortex-Induced Vibration for Aquatic Clean Energy converter is an alternating lift technology converter (ALT) utilizing flow-induced oscillations (FIOs) to harness power from currents/tides/rivers. This paper reviews the underlying concepts and all research breakthroughs made in the ALT over the last ten years by the Marine Renewable Energy Laboratory. Various scale-prototypes and virtual damper-spring systems have been developed to investigate FIOs systematically and, thus, find ways to enhance them for harnessing hydrokinetic energy more efficiently. Applying passive-turbulence control and utilizing the synergy of multiple cylinders, the ALT is able to work over a broad range of flow speeds and extract more hydrokinetic energy. The efficiency of laboratory-prototypes and large-scale prototypes tested in a river reached 52% and 20%, respectively. Furthermore, several field-tests show that the ALT is environmentally friendly and financially competitive based on the estimation of the levelized cost of energy. • An alternating-lift converter was tested in the MRELab and St. Clair River for 10yrs. • Converter uses passive turbulence control and synergistic flow-induced oscillations. • The power efficiency of the ALT converter reaches 88% of the Betz limit. • Adaptive harnessing damping increases single-cylinder power output by 25%. • The ALT presents a viable Current Energy Converter technology that is environmentally compatible. [ABSTRACT FROM AUTHOR]