Electrical Energy Storage Systems for the Energy Networks with Dispersed Generators

Dispersed electrical energy storage systems are expected to work for load leveling, fluctuation smoothing, uninterruptable power supply and emergency power source. Their introduction seems to be essential in order to control the future complicated energy utility networks since they can handle both active and reactive power. In this paper, the problem of the future electric distribution utility has been pointed out, and the characteristics of promising energy storage systems, such as pumped hydro, CAES, secondary batteries, SMES, flywheel and capacitors have been investigated and compared with each other. From the result of the investigation, their suitable application fields have been clarified.