Low-carbon policy simulation for cost-effective decarbonization pathways of China's hydrogen production considering regional heterogeneity

China's hydrogen production sector is confronted with the dual challenge of high-carbon lock-in risks and significant regional disparities in resource endowments, necessitating regionally tailored low-carbon transition strategies. Existing studies lack a systematic integration and quantitative assessment of multi-technology hydrogen production pathways alongside market- and finance-based policy instruments at the provincial level. To bridge this gap, we construct a high-spatial-resolution Long-term Provincial Hydrogen Production Pathway Planning (LP-HPPP) model that integrates provincial resource heterogeneity and diversified hydrogen production technology portfolios while coupling multiple policy modules to simulate the transition pathway of China's hydrogen production system. Results indicate that under the baseline scenario, most provinces will struggle to replace grey hydrogen with green hydrogen by 2035, with national cumulative carbon emissions projected to reach 14,352 Mt. by 2050. The synergistic implementation of carbon trading, green certificates, and green credit substantially enhances emission reduction performance, achieving provincial mitigation rates of 25.62%–84.59% at unit costs of 2.75–628 CNY/t CO₂, while advancing the green hydrogen substitution inflection point by 5 to 15 years across most regions. Policy effects also exhibit pronounced regional heterogeneity: based on carbon trading mechanisms, prioritizing green credit proves more cost-effective for coastal provinces, whereas central and western regions are better suited to green certificate instruments. This research provides a scientific basis for differentiated market-based transition pathways, while its adjustable framework ensures strong international transferability to regions confronting similar challenges.