consumed during each unit time duration relatively small for example it becomes possible to make them smaller than the power amount wpu shown in fig4 accordingly it becomes possible to alleviate the maximum value of the system power amount consumed during the unit time duration and it becomes possible to reduce the power rate further it is enough to only slightly change the time duration for performing the recharge operation of the recharge portion 11 accordingly it is not necessary to limit the recharge time zone to late night early morning and the like accordingly it becomes possible to easily reduce the power rate without limiting the recharge time zone besides in the case where the recharge portion 11 performs a plurality of the recharge operations the time duration for performing each recharge extends into unit time durations different form each other because of this it becomes possible to alleviate the system power amount which is consumed by the plurality of recharge operations of the recharge portions 11 being distributed to the overlapping unit time durations and it becomes possible to alleviate the system power amount consumed during the unit time durations becoming large in the meantime in the recharge operation that is performed during the time duration of 12 20 12 40 shown in fig5 the middle time 12 30 and the.