Energy storage in smart grids

Conventional power plants generate electricity using fossil fuels (oil, coal, and gas). These power plants are far away from the load area, and transmission and distribution systems are required to manage the load from the conventional power plant. In conventional power plants, most of the issues with grid ancillary services are solved by the large generators themselves. With the advancements and innovations in renewable energy sources and their harnessing techniques, distributed generation has become a novel concept, and the energy storage system (ESS) is an essential component of the hybrid energy system and the smart grid. The ESS helps in mitigating the intermittency of renewable energy sources; it also helps in bridging the gap between energy production and energy demand. With the intermittent and unpredictable nature of renewable energy sources like solar and wind, grid ancillary services are not easy to obtain. The ESS is the best solution to incorporate these services. The ancillary services include grid stabilization, renewable energy integration, power quality, frequency regulation, load following, peak shaving, spinning reserve, time-shifting, and transient stability. Energy is stored in mechanical, chemical, and electrical forms. In mechanical form, energy storing technologies are pumped hydro ESSs, compressed air ESSs, and flywheel ESSs. In chemical form, energy is stored in batteries, flow batteries, and regenerative fuel cells. In electromagnetic form, energy is saved in capacitors, supercapacitors, and superconductors.