Techno-economic assessments (TEAs) of energy storage technologies evaluate their performance in terms of capital cost, life cycle cost, and levelized cost of energy in order to determine how to develop and deploy them in the power network.
An ESS stores electricity when demand is low and discharges when demand is high, providing great operational flexibility to the electrical grid and mitigated intermittency , , , . Transportation, portable devices, and the power network are the typical application areas for an energy storage system , , , , .
Energy storage devices are used in the power grid for a variety of applications including electric energy time-shift, electric supply capacity, frequency and voltage support, and electricity bill management . The number of projects in operation by storage type for different services is provided in Table 2.
An overview of energy storage technologies Although energy storage technologies can be categorized by storage duration, response time, and function , , the most popular method is by the form of energy stored, broadly classified into mechanical, thermochemical, chemical, electrical, and thermal energy , , , .
Cost models The power conversion system (PCS), storage unit (SU), and balance of plant (BOP) are the three main components of an energy storage system. The PCS includes several electrical power devices (e.g., inverter, transformer, etc.) that regulate voltage, current, and frequency based on the load pattern.
Testing items and procedures, including type test, production test, installation evaluation, commissioning test at site, and periodic test, are provided in order to verify whether ESS applied in EPSs meet the safety and reliability requirements of the EPS.