Flywheel energy storage price growth rate

Flywheel energy storage systems are considered essential in these investments, allowing better utilization of existing and new energy resources. Therefore, the energy sector's considerable investments are projected to propel the regional demand for flywheel energy storage systems in the coming seven years.

Datasheet from a long term flywheel energy storage retailer shows their solution at ~86% efficient. The full details give a better view: a 32kWh storage what consumes 55W when idle and consumes 140W when charging/discharging at 8kW. For off-grid where you store the power for 20 hours at time the 55W draw will be pretty costly.

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.

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.

Re specific energy: For a stationary system, energy stored per unit volume probably is more relevant that energy stored per unit mass. Domestic flywheels are unlikely to happen for 3 reasons: They must be heavy to store significant energy.

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).