Global renewable hydrogen certification: Frameworks, gaps, and policies

Green hydrogen, produced through water electrolysis using renewable electricity, is increasingly recognised as a means of reducing greenhouse gas emissions across the energy system. Its high energy density supports long-duration energy storage, while its chemical flexibility enables use as a low-carbon feedstock for ammonia, methanol, and other electro fuels. Green hydrogen is important for decarbonising hard-to-abate sectors such as steel production, maritime transport, and other energy-intensive industries where direct electrification remains limited. However, its environmental credibility and market acceptance depend on certification systems that consistently and transparently quantify lifecycle greenhouse gas emissions and related sustainability attributes. This study examines hydrogen certification from a global perspective, focusing on technical design, regulatory approaches, and governance arrangements. A comparative analysis of existing certification schemes is conducted, with emphasis on system boundary definitions, emissions accounting methods, greenhouse gas threshold values, and monitoring, reporting, and verification requirements. Unlike studies limited to individual schemes or regions, this paper adopts a system-level approach linking technical certification rules with governance and implementation practices across regions. The analysis identifies substantial variation among certification schemes, including differences in the scope of lifecycle assessment, handling of upstream electricity emissions, reliance on default versus project-specific emission factors, and inclusion of broader sustainability criteria. These differences reduce interoperability, increase uncertainty for project developers, and create barriers to cross-border hydrogen trade. The paper identifies five policy priorities: shared technical baselines and emissions thresholds; interoperable digital traceability tools; alignment with international accounting standards; inclusive stakeholder participation; and progress toward mutual recognition between countries. • Mutual recognition of certification schemes enables global adoption. • Inconsistent system boundaries, GHG thresholds, verification methods, and governance across schemes. • Inconsistent system boundaries, GHG thresholds, verification methods, and governance across schemes. • Standardised technical baselines and traceability tools enhance transparency and credibility. • Alignment with ISO 14067 and EU RED III ensures regulatory coherence and stakeholder confidence.