抄録
Japan enacted legislation in 2021 incorporating the aim of achieving net zero greenhouse gas (GHG) emissions by 2050 based on temperature targets set in the Paris Agreement. Our research attempted to quantitatively express the combination of technologies, energy supply and demand, and structure of GHG emissions required to achieve net zero GHG emissions by 2050. The combination of measures necessary to achieve this goal was estimated by using a computable general equilibrium model, a technology selection model and an optimal generation planning model while considering factors including the consistency of the future economy and energy demand, feasible technology deployment speed and the maintenance of regional and temporal balances for electricity demand and supply. The results show that major changes in the energy system will be necessary, including shifting from fossil fuel to electricity, expanding the use of hydrogen and hydrogen-based fuels, and expanding the use of renewable energy. Also, negative emission measures will be required to address residual emissions. In addition, reducing energy demand through social transformation was shown to reduce dependence on measures the efficacy of which is highly uncertain and thereby increase the possibility of achieving net zero GHG emissions. These findings are also applicable to building a decarbonized society in Asian countries, while taking into account each country’s stage of development and taking advantage of climatic and regional characteristics.
