What are Flywheel Energy Storage Systems?

Flywheel Energy Storage Systems are interesting solutions for energy storage, featuring advantageous characteristics when compared to other technologies. Research focuses on cost aspects, system reliability, and energy density improvement for these systems. In this context, a novel shaftless outer-rotor layout is proposed.

Are flywheel batteries a good energy storage system?

Flywheel batteries are probably the most compact energy storage systems that can be designed with the lowest environmental impact and highest durability. Not quite domestic, but the technology keeps maturing. It's better suited for leveling short-lived and massive power needs rather than storing energy for days (note the 7%/hr loss below).

Are flywheels viable for utility-scale energy storage?

Flywheels are only viable for utility-scale energy storage when multiple units can be integrated into an array to achieve the necessary storage capacity. Developing hardware, software and a test platform is necessary to successfully demonstrate multi-unit array operation with balanced power and state of charge (SoC).

How much energy is stored in a flywheel?

At the MIT Magnet Laboratory, energy is stored in huge solid flywheels of mass 7.7 times 10^4 kg and radius 2.4 m. The flywheels ride on shafts 41 cm in diameter. If a frictional force of 34 kN acts tangentially on the shaft, how long will it take the flywheel to come to a stop from its usual 360 rpm rotation rate?

Can a flywheel be used as an energy storage farm?

For flywheels, large arrays of units installed as an “energy storage farm” will be commonplace. The hardware and software to manage and control multiple units was developed. During the project activities, arrays of up to four units were operated through multiple power cycles under a range of operating scenarios.

Can flywheels save energy?

Installing 100 MW’s worth of flywheels used for distribution can reduce demand charges by $36 million and provide $8 million of energy savings a year since the FESS can eliminate mid-day peak and evening peaks of electricity use. Lithium battery technology can only do one peak reduction a day.