Development of a Hydraulic Energy Storage System for Hybrid Wind Turbine Transmissions

Abstract

Mid-size wind turbines are an under-recognized means to help prevent irreversible climate damage caused by unprecedented human-made carbon emissions. A high-power hydraulic energy storage system can be added to turbine transmissions to capture energy in high wind speeds, and release energy in low wind speeds. The hybrid system stabilizes the output power of the transmission, and increases reliability while offering ancillary benefits such as fault-ride through and pitch and yaw control in severe weather. The hybrid system was constructed. Experimental characterization of hybrid parameters determined that a modified heat transfer model of the accumulator is realistic, and that the thermal time constant of the accumulator is around 80 seconds. A high fidelity simulation is produced which is experimentally validated. The simulation is then used to find the additional annual energy production compared to the non-hybrid system is 3.5%. This value can only be attained with the addition of a clutch and directional valve.