Compressed air energy storage flywheel energy storage

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.

Flywheel energy storage systems store energy in a rotating flywheel, which can be later used to generate electricity. They have a low discharge rate and can respond quickly to changes in demand. However, they have a low storage capacity and high initial investment costs.

Thanks to the unique advantages such as long life cycles, high power density, minimal environmental impact, and high power quality such as fast response and voltage stability, the flywheel/kinetic energy storage system (FESS) is gaining attention recently.

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.

CAES efficiency depends on various factors, such as the size of the system, location, and method of compression. Typically, the efficiency of a CAES system is around 60-70%, which means that 30-40% of the energy is lost during the compression and generation process. What is the main disadvantage of compressed air-based energy storage?

High-strength steel flywheels have a high energy density (volume-based energy) due to their high mass density. Furthermore, they are superior to composite ones regarding thermal conductivity and design data availability, such as SN curves and fracture toughness.