Electric power companies will use data and digital technology to encourage power-saving behavior based on electricity deregulation policies such as dynamic pricing and demand response, to manage both stable electricity supply and decarbonization during times of power shortage (i.e., Green Transformation: GX). In this paper, we used data sets of electricity supply and demand, weather and wholesale electricity market in the TEPCO area after April 2016, and we constructed and analyzed the impact assessment model of the wholesale electricity market on maximum electricity demand. Then, we assessed the impact of electricity deregulation policies on GX and verified its effectiveness.