JMIP 2 Part 1: Technology uncertainty and robustness in Japan’s net-zero pathways

Abstract

Japan’s commitment to reach net-zero 2050 hinges on innovation in emerging, uncertain technologies. Yet, no study has systematically examined uncertainties in technology development for Japan’s net-zero goal in a multi-model framework. Here, we close this research gap by presenting the results of the Japan Model Intercomparison Project (JMIP) 2. Across models and technology scenarios with wide spreads in costs of emerging technologies, we consistently identify the following robust strategies for net zero: (1) reducing unabated fossil fuels, (2) improving economy-wide energy efficiency, (3) decarbonizing the power sector, and (4) deploying carbon dioxide removal. We also find that although the expansion of variable renewable energy and end-use electrification is robust, the precise level in 2050 remains uncertain. Using technology sensitivity scenarios, we show that the marginal cost of abatement (or carbon price) is significantly affected by the availability of carbon removal. Affordability of hydrogen and ammonia imports significantly affects primary energy supply in some models, underscoring a policy architecture that can flexibly adapt as the techno-economic landscape evolves.