In this paper, a method to calculate electricity demand in the region based on scenarios regarding the future introduction of PV(photovoltaic system) and EV(Electric Vehicle) to the region were developed and were conducted trial calculations for Aichi Prefecture. The main findings are as follows: 1) Annual net electricity demand in Aichi Prefecture will tend to decline as the number of residences decreases and PV penetration increases; if only EVs are deployed as targeted by the government and PV penetration is slow, the decline will be moderate. 2) As of 2050, regardless of scenario, the demand curve will be duck-curved in Aichi Prefecture as a whole. This trend will be particularly severe during May holidays when electricity load is low, and net electricity demand will be negative in Aichi Prefecture if PV penetration is as high as the government target. 3) The impact on net electricity demand will vary by region, with a small impact in the central Nagoya area, but a larger impact in the suburbs, and an increase in the number of regions where net electricity demand will be negative, either temporarily or as an annual total.