Abstract
Hydrogen plays a crucial role in the global transition to cleaner energy, offering a path to reduce carbon emissions in industries, transportation, and energy storage. To assess its environmental impact, life cycle assessment (LCA) is a vital tool. However, the application of LCA varies significantly across countries, leading to differences in methods, results, and standards. These inconsistencies make it challenging to establish a unified approach for assessing hydrogen’s contribution to global sustainability. This study benchmarks global hydrogen LCAs by analysing methodologies, functional units, system boundaries, and impact categories, drawing insights from the latest published studies and government reports. Key findings reveal how regional energy mixes, production technologies, and policy incentives influence the carbon emissions associated with hydrogen production. The review highlights challenges such as methodological inconsistencies and the absence of standardized frameworks. This work provides a foundation for enhancing hydrogen sustainability assessments and offers strategic insights for the global hydrogen economy.
