Optimal capacity of Battery Energy Storage System and its effect of CO ₂ reduction

Battery Energy Storage System (BESS) is attracting attention all over the world. NAS (Sodium and sulfur) battery is one of the most promising BESSs, and it has been widely used by various customers in Japan. Although the conventional incentive to install NAS battery was load leveling, the recent users' interests are not unique. Renewable energy expansion by reducing greenhouse gases such as CO2 against global warming is another strong incentive. In this paper, the economic advantage in introducing BESS is investigated as a new way of achieving of best mix. BESS can reduce both of the construction cost and the operation cost of generators. The reduction of CO2-emission, which is a worldwide obligation, can be performed by introducing BESS. In this paper, a numerical analysis of the optimal amount of BESS by evaluations of CO2-reduction and cost benefits is demonstrated.