What is the energy density of flywheel storage?

Steel flywheels: 5–30 Wh/kg. Carbon fiber composite flywheels: 100–200 Wh/kg. For comparison, Li-ion batteries: 150–250 Wh/kg. Flywheels trade lower energy density for higher power density and longer cycle life.

What is the round-trip efficiency of flywheel storage?

Modern vacuum-enclosed magnetic bearing flywheels achieve 85–95% round-trip efficiency. Self-discharge (standby losses) is 3–20% per hour — making flywheels unsuitable for multi-hour energy storage.

What applications suit flywheels?

Flywheels excel at: UPS (millisecond response), frequency regulation (seconds to minutes), bridging power for microgrid islanding, and absorbing regenerative braking in transit systems (trains, elevators).

Flywheel Energy Storage Density Calculator

Calculate flywheel energy storage capacity, power rating, and round-trip efficiency. Compare carbon fiber vs steel flywheels for UPS and frequency regulation applications.

2D stress state at a point. All stresses in MPa.

σx — Normal Stress X (MPa)

σy — Normal Stress Y (MPa)

τxy — Shear Stress (MPa)

⚙ Mechanical Note: Results are based on standard textbook formulas and ISO/AASHTO references. Always verify critical designs with applicable codes (ISO 898, AASHTO 1993, AISC, Eurocode 3) and a qualified engineer.

How to Use

Enter the values for the patient or scenario you are assessing. Calculate flywheel energy storage capacity, power rating, and round-trip efficiency. Compare carbon fiber vs steel flywheels for UPS and frequency regulation applications. Use the flywheel storage density result to inform your clinical assessment.

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Flywheel Energy Storage Density Calculator

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Frequently Asked Questions

What is the energy density of flywheel storage?

What is the round-trip efficiency of flywheel storage?

What applications suit flywheels?