Electrical Energy Storage is a process of converting electrical energy into a form that can be stored for converting back to electrical energy when needed (McLarnon and Cairns, 1989; Ibrahim et al., 2008). In this section, a technical comparison between the different types of energy storage systems is carried out.
A battery energy storage system (BESS) is an electrochemical storage system that allows electricity to be stored as chemical energy and released when it is needed. Common types include lead-acid and lithium-ion batteries, while newer technologies include solid-state or flow batteries.
The length of time an ESS can supply electricity varies by energy storage project and type. Energy storage systems with short durations supply energy for just a few minutes, while diurnal energy storage supplies energy for hours.
During off-peak periods at night, potential energy is stored by pumping water from the lower to the upper reservoir. During peak hours at daytime, the water is released back to the lower reservoir, thus generating electrical power. Compressed air energy storage (CAES) Systems: these systems use compressed air as the energy storage medium.
In the electricity market, global and continuing goals are CO 2 reduction and more effi cient and reliable electricity supply and use. The IEC is convinced that electrical energy storage will be indispensable to reaching these public policy goals.
Electrical energy storage systems (EESS) for electrical installations are becoming more prevalent. EESS provide storage of electrical energy so that it can be used later. The approach is not new: EESS in the form of battery-backed uninterruptible power supplies (UPS) have been used for many years. EESS are starting to be used for other purposes.