Analysis of short-term energy storage for midsize hydrostatic wind turbine1

This paper presents a novel method of capturing more energy from the wind using short-term energy storage in a hydrostatic wind turbine. A hydrostatic transmission (HST) not only provides reliable operation but also enables energy management features like energy regeneration using hydraulic accumulators. In this study, turbulence-induced wind transients occurring near the rated power are exploited to extract more energy from the wind. Wind characteristics are analyzed to develop models to quantify the energy losses due to the wind turbulence and the potential energy gains from the short-term energy storage. A dynamic simulation model of the hydrostatic wind turbine and the proposed energy storage system is developed. A rule-based control strategy for the energy storage is proposed. Results show that in a 50 kW hydrostatic wind turbine, the annual energy production (AEP) can be increased by 4.1% with a 60 liter hydraulic accumulator.