Status of pilot projects using flywheels for frequency regulation

Grid frequency regulation function addresses the balance between a grid network load and power generated. The system operator generates a frequency regulation signal based on the difference between these two parameters. The goal is to keep the system near nominal 60 or 50 Hz. Traditionally, frequency regulation is managed by varying the output of fossil fuel or hydro generators connected to the electric grid. As an economical alternative, energy storage can be used to provide this service, first, absorbing energy when it is in abundance, then discharging the same for the desired frequency regulation effect. Two flywheel based pilot projects are supported by DOE, California Energy Commission and NYSERDA in NY. The California system has been delivered and connected to the grid at PG&Es DUIT development facility in San Ramon CA. The NY system is in final assembly and will be delivered to Power and Composite Technologies, an industrial user in Amsterdam NY near the end of a distribution feeder. This paper describes and summarize the data generated at these two sites. The objective is to include performance characteristics, quantify ability to deliver reactive power, show results comparison using a variety of control schemes, and estimate economic benefit