Maseru Carbon Flywheel Energy Storage

Flywheel energy storage systems are feasible for short-duration applications, which are crucial for the reliability of an electrical grid with large renewable energy penetration. Flywheel energy storage system use is increasing, which has encouraged research in design improvement, performance optimization, and cost analysis.

Steel rotor and composite rotor flywheel energy storage systems were assessed for a capacity of 20 MW for short-duration utility applications. A consistent system boundary was considered for both systems with the life cycle stages of material production, operation, transportation, and end-of-life.

The use of new materials and compact designs will increase the specific energy and energy density to make flywheels more competitive to batteries. Other opportunities are new applications in energy harvest, hybrid energy systems, and flywheel's secondary functionality apart from energy storage.

The main components of a flywheel energy storage system are a rotor, an electrical motor/generator, bearings, a PCS (bi-directional converter), a vacuum pump, and a vacuum chamber . During charging, the rotor is accelerated to a high speed using the electrical motor.

The net energy ratios of steel and composite flywheels are 2.5–3.5 and 2.7–3.8. The GHG emissions of steel and composite flywheels are 75–121 and 49–95 kg CO 2 eq/MWh. Flywheel energy storage systems are feasible for short-duration applications, which are crucial for the reliability of an electrical grid with large renewable energy penetration.

While many papers compare different ESS technologies, only a few research, studies design and control flywheel-based hybrid energy storage systems. Recently, Zhang et al. present a hybrid energy storage system based on compressed air energy storage and FESS.