世界および日本における中長期温暖化対策としての天然ガスの貢献に関する分析

抄録

The Paris Agreement including long-term goals of 2 ℃, 1.5 ℃ and net zero emissions in the second half of this century. Natural gas is the lowest emissions per calorie among fossil fuels and can contribute to CO₂ emission reductions. On the other hand, it is one of the fossil fuels and emits CO₂ through its combustion. There are uncertainties in long-term emission reduction pathways or timings even for the 2 ℃ goal for example due to its different achieving probability of the temperature target. In addition, there are large uncertainties in technologies and socioeconomic conditions. This study evaluated the role of natural gas as medium- and long-term global warming countermeasures in the world and Japan by using a global energy systems model having disaggregated regions and detailed technology descriptions. The energy systems focusing natural gas until 2050 were discussed but the model estimated them intertemporally until 2100 including net CO₂ zero emissions for the 2 ℃ scenario. According to the analyses, natural gas will play a larger role for emission reductions until 2050 both in the world and Japan even for the deep emission reduction pathways consistent with the 2 ℃ goal. Co-generation systems will play a large role in all of power, industry and residential and commercial sectors particularly in Japan in general, while the contribution becomes small when the utilization of heats is limited.