International Energy Agency recommends reducing CO2 emissions to zero in 2050. In recent years, renewable energy has been increasing because decarbonization is essential in the energy sector. However, due to output fluctuations of solar and wind power generation, demand-supply balancing requires other power sources and energy storage. Therefore, we focus on hydrogen as feasible energy storage. We reconsider renewable energy and next-generation nuclear power plant as the power source for hydrogen production. In this study, considering the use of hydrogen, we analyze the feasible future energy generation from CO2 reduction and economic efficiency using linear mathematical modeling. The result shows that hydrogen plays a role in balancing peak demand with pumped storage power generation in 2050. Thermal power would be replaced with hydrogen as a demand regulator in the future.