Is mechanical energy storage a new type of energy storage

Mechanical storage systems work on the basis of storing available and off-peak excessive electricity in the form of mechanical energy. Once the demand for electricity power overcome the available energy supply, the stored energy would be release to meet with the energy demand.

Unlike thermal storage, mechanical energy storage enables the direct storage of exergy. An attractive feature of the various types of mechanical energy storage is the simplicity of the basic concept. The challenge in developing mechanical storage systems is often the limited storage density, which is lower than most other energy storage concepts.

Hence, mechanical energy storage systems can be deployed as a solution to this problem by ensuring that electrical energy is stored during times of high generation and supplied in time of high demand. This work presents a thorough study of mechanical energy storage systems.

The three main categories of mechanical energy storage systems are FESS, PHES and CAES. FESS is based on storing energy for short durations in the form of kinetic energy by using a rotating mass. Indeed, it has the fastest response where it can discharge huge amount of power in few minutes however its capacity is very limited.

Mechanical energy storage systems are very efficient in overcoming the intermittent aspect of renewable sources. Flywheel, pumped hydro and compressed air are investigated as mechanical energy storage. Parameters that affect the coupling of mechanical storage systems with solar and wind energies are studied.

Energy storage technologies with high energy capacity like PHS, compressed air energy storage (CAES), and gravity energy storage (GES) can provide excellently the black start service to the grid. There are six different categories of ESS, and these are: mechanical, thermal, chemical, electrochemical, electrical and hybrid system.