Unit capacity cost of flywheel energy storage

Equipment cost distribution for the flywheel energy storage systems. FESSs are used for short-duration power applications. Therefore, power capital cost ($/kW) could be a useful parameter to compare the economic feasibility of energy storage systems for similar power applications.

Utility-scale energy storage systems for stationary applications typically have power ratings of 1 MW or more . The largest flywheel energy storage is in New York, USA by Beacon Power with a power rating of 20 MW and 15 min discharge duration .

However, almost no bottom-up research has been done, i.e., research that considers the technical parameters to size the components of a flywheel storage system, estimate cost parameters based on the design, and provide a probable distribution of the total investment cost and levelized cost of storage.

The largest flywheel energy storage is in New York, USA by Beacon Power with a power rating of 20 MW and 15 min discharge duration . Utility-scale flywheel storage is typically used for frequency regulation to maintain grid frequency by matching electricity supply and demand for a short period, usually 15 min, .

A bottom-up cost model was developed to assess the levelized cost of flywheel storage. Composite and steel rotor flywheels were assessed for frequency regulation. The steel rotor flywheel has a lower capital cost and levelized cost of storage. The costs of composite and steel rotor flywheels are $190 and $146/MWh, respectively.

The costs of a power converter for composite and steel flywheels are $49,618 and $52,595, respectively. The cost difference is due to the difference in rated power, 100 kW for the composite flywheel and 108 kW for the steel flywheel. Fig. 5. Equipment cost distribution for the flywheel energy storage systems.