2025-10-06 イェール大学
＜関連情報＞
- https://environment.yale.edu/news/article/harvesting-hydrogen-biomass-energy-can-provide-substantial-carbon-emissions-reduction
- https://www.pnas.org/doi/full/10.1073/pnas.2519606122
米国における水素の短期的な気候への恩恵に関する需給戦略 Supply–demand strategies for near-term climate benefits from hydrogen in the United States
Youyi Xu, Wei Peng, and Yuan Yao
Proceedings of the National Academy of Sciences Published:October 6, 2025
DOI:https://doi.org/10.1073/pnas.2519606122
Significance
Hydrogen (H2) is critical for energy decarbonization. Previous H2 research has overlooked key dynamics in H2 supply and demand. Our study reveals that the H2 supply mix is crucial for greenhouse gas (GHG) mitigation, with biomass-based H2 providing substantial reductions in the near term when carbon pricing or large-scale advanced water electrolysis is unavailable. On the demand side, our results identify a misalignment between H2 deployment and GHG mitigation intensity: industrial sectors show higher GHG mitigation intensity but receive limited H2, while transportation sectors consume most H2 despite lower mitigation intensity. This highlights missed opportunities for maximizing emissions reductions. Our findings underscore the need to integrate clean H2 production incentives with sector-specific demand-side strategies to support national decarbonization goals.
Abstract
Hydrogen (H2) is a promising energy carrier for decarbonization. However, the greenhouse gas (GHG) mitigation potential of the H2 supply and its adoption across various demand sectors in the US remains unclear. Here, we couple prospective life cycle assessment with a process-based integrated assessment model to evaluate the GHG mitigation of H2 from supply and demand perspectives. Our results show the critical role of H2 production mix in determining supply-side GHG mitigation potential. Without national carbon pricing or large-scale electrolysis in the near future, biomass-based H2 (Bio-H2) emerges as a critical transitional clean H2 production technology. Bio-H2 reduces the life cycle GHG emission intensity of the H2 supply mix by 1.8 to 5.5 kg CO2 kg−1 H2, resulting in a national reduction of 606 to 1,706 Mt CO2e from 2025 to 2050. This represents 1.6 to 2 times greater mitigation potential compared to scenarios without Bio-H2. On the demand side, we identify a misalignment: industrial sectors with high mitigation intensity (e.g., iron and steel, 147 Mt CO2e EJ−1) receive limited H2 deployment (0.8 EJ), while the transportation sector accounts for 75% of H2 use (e.g., passenger and light-duty vehicles, 10 EJ) despite their lower mitigation intensities (54 Mt CO2e EJ−1). While economy-wide climate policies (e.g., carbon prices) could direct more industrial H2 usages, implementing these policies is challenging; sector-specific strategies can be more practical. Our results highlight the importance of near-term support for Bio-H2 and sector-specific demand strategies to enhance the climate effectiveness of US H2 deployment.
