If both EVs (Electric Vehicles, includes plug-in hybrid electric vehicles) and renewable energies spread in large quantities, it is possible to control the supply fluctuation of renewable energies using the storage battery of EVs. This research tried to show the charge load potential of EVs based on the state of the Japanese passenger car using traffic census results etc. Furthermore, it tried to show trend of the storage battery capacity according to time. From the estimated result; (1) the charge electricity of low and middle distance gets a majority of the total charge demand, (2) charge load changes according to time several times, and the minimum load is the number of GWh at early morning, (3) if night charge is assumed, the standby charge demand of noon will reach tens GWh, it may have sufficient scale for supply fluctuation control of PVs. Although the present EV is not suitable for long-distance running, these are expected to be 30 or less percent of the total charge demand. The estimated storage capacity potential in this research will not change numbers of times.