Pathways to deep decarbonization: integrating H2–NG blends, flexible storage, and sector coupling in a policy-driven energy model

Energy systems worldwide face converging crises: constrained natural gas supplies, ambitious decarbonization mandates, and inadequate energy storage. We present a high-resolution multi-sector planning model with hourly operational detail that co-optimizes electricity, gas, and hydrogen networks under coordinated decarbonization pathways. The model innovatively integrates hydrogen production (via steam methane reforming with carbon capture and waste gasification), 15% hydrogen blending into gas grids, and multi-timescale energy storage (batteries for grid balancing, molten-salt thermal storage for long-duration) to enhance flexibility. We simulate progressive pathways targeting 30%, 50%, and 70% CO 2 emission cuts (with concurrent natural gas use reductions of 10–50%). Results show that without new measures, fossil reliance grows unchecked, spurring rising emissions and gas demand, whereas moderate pathways achieve modest emissions declines through initial renewable deployment and partial H 2 integration. Under deep decarbonization (∼70% CO 2 cut), renewable generation expands drastically and hydrogen storage exceeds 0.7 Mt, enabling extensive fuel switching and driving a roughly 75% drop in grid CO 2 intensity (from 1373 to 362 tCO 2 /MWh). Sensitivity analyses show carbon pricing, fuel costs, and hydrogen economics strongly influence outcomes; nevertheless, integrated H 2 -electricity storage consistently yields greater system flexibility and cost-effective emission abatement. The model serves as a transferable, crisis-responsive planning tool, equipping policymakers to coordinate deep decarbonization across power, gas, and hydrogen systems.