Grid integration of energy storage

Electricity as a commodity is markedly different from other commodities in the sense that it must, in general, be consumed when it is produced. The capability to store energy for a later use can help to improve the flexibility of power system operation by providing control of power as and when required. With a strong push towards increasing the reliance on renewable energy resources, a flexible power system is desired; one that can accommodate increased variability and uncertainty of generating resources. Energy storage is one strategy for enhancing the flexibility of power system operation. The application for energy storage can be broadly classified into energy applications (bulk transfer of energy from one time to another) and power applications (fast injection/absorption of power). There is also a broad spectrum between energy and power applications. The selection of a storage system as a means of adding flexibility to the grid depends upon a number of factors: cost being an important one. Other strategies that can offer flexibility in today's power system include demand response and fast-start generation with high ramping potential.