リチウムイオン蓄電池を搭載した家庭用PEFCコージェネレーションシステム導入による一次エネルギー量とCO<sub>2</sub>排出量削減効果の評価

Abstract

This paper presents the effects of introduction of residential polymer electrolyte fuel cell (PEFC) co-generation system with batteries in comparison with conventional systems that consist of a gas boiler and electric power from commercial grid, by computer simulation. The PEFC co-generation system in commercial use provides the average primary energy saving rate of 12.7% and CO2 reduction rate of 15.4% with respect to the conventional system. Addition of 8.0-kWh batteries to the PEFC system results in limited improvements of 0.8 points and 0.9 points in the reduction rates, respectively, yielding 13.5% and 16.3%, when using a conventional operation planning method. A new operation planning method is proposed in order to make a precise control of charging and discharging the batteries. The average primary energy saving rate reaches up to 16.9% by the improvement of 4.2 points, and CO2 reduction rate reaches up to 20.4% by the improvement of 5.0 points in the PEFC co-generation system with 8.0-kWh batteries using the new operation planning method. The new method can thus realize a substantial improvement in reduction rates. Furthermore, it is shown that the suitable battery module capacity for the residential PEFC co-generation system is 4.0kWh.