Supply-demand strategies for near-term climate benefits from hydrogen in the United States.

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.