Paper No 315 – Status on the Electric-thermal Energy Storage Technology and Application of a Supercritical Carbon Dioxide Power Cycle – 13th IEA Heat Pump Conference, Jeju, Korea
A large-scale energy storage system becomes more essential as a proportion of the renewables increases in the future electricity supply mix. Intermittent electricity supply characteristics by renewables causes instability of a grid, therefore electricity time shift technologies are needed. Batteries are representative electricity energy storage system, however, it is hard to expand for large-scale system, because of high cost, short discharge duration characteristics. The electric-thermal energy storage technology, recently called as a Carnot Battery, has been focused as a solution for the large-scale grid level energy storage applications, because it uses conventional robust heat engine technologies suitable for large-scale system. It is composed of electricity-toheat, heat storage and heat-to-electricity system. In case of heat-to-electricity, a supercritical carbon dioxide power cycle (sCO2) is attractive option because of its potentials of wide operation range, dry-cooling, high efficiency and small foot print. Korea Institute of Energy Research (KIER) has been developed a sCO2 power cycle test loop with the turbomachinery. In this paper, concept of the electric-thermal energy storage and the technical development highlights of the sCO2 power cycle in KIER are presented.