Energy storage  is regarded as a useful solution to manage the reliability and stability difficulty of future power systems. It will also solve the problem faced by the power industry. The principle of energy storage is conversion of renewable energy into storable energy at the times of either low demand or low generation cost. Stored energy are converted to electrical energy under necessary condition and at times of high demand or high generation cost.

 It has great significance in different sectors which are ranging from large-scale generation and transmission-related systems to distribution networks or customer sites.

Here are the criteria for the selection of an energy storage technique

1) the available energy resources

2) energy requirement and application

 3) energy storage efficiency

 4) energy storage cost

 5) energy storage infrastructure

6) other factors.

Different energy storage technologies are described below

1) Pumped hydro system

It consists of 2 water reservoirs. Water reservoirs at a higher elevation store energy at off-peak hours which is called as charging process. Water reservoir from upper elevation discharges and flows through the hydro turbine to generate electrical energy. This system is highly efficient, largest power, and has a long lifetime

2) Compressed Air Energy storage

This system compresses air and stores it in an underground structure( rock structure, salt) or above-ground system of vessels or pipes. The compressed air is released during the necessary situation to produce energy.

3) Battery Energy Storage System (BESS)

Storage of electricity is done in form of chemical energy. The battery system comprises power battery cells that are combined in either parallel or series to produce a required electrical characteristic. Each cell consists of a liquid, paste, or solid electrolyte together with a cathode or anode. Due to a chemical reaction under a potential applied to both electrodes charging of the battery is done

4) Superconducting Magnetic Energy Storage

When DC is circulated through a superconducting coil then it produced a magnetic field in which energy is stored. The coil is held in the superconducting to prevent the losses which are brought on the current flow. It has a very quick response so power is almost available instantaneously.