A review on the environmental performance of various hydrogen production technologies: An approach towards hydrogen economy

Demand for hydrogen has grown and continues to rise as a versatile energy carrier. Hydrogen can be produced from renewable and non-renewable energy sources. A wide range of technologies to produce hydrogen in an environmentally friendly way have been developed. As the life cycle assessment (LCA) approach has become popular recently, including in the hydrogen energy system, this paper comprehensively reviews the LCA of hydrogen production technology. A subdivision based on the trends in the LCA studies, hydrogen production technology, goal and scope definition, system boundary, and environmental performance of hydrogen production is discussed in this review. Thermochemical hydrogen production is the most studied technology in LCA. However, utilizing natural resources, especially wind power, in the electrolysis process stands out as an environmentally preferable solution when compared to alternative production processes. It is crucial to rethink reactors and other production-related equipment to improve environmental performance and increase hydrogen production efficiency. Since most of the previous LCA studies were conducted in developed countries and only a few were from developing countries, a way forward for LCA application on hydrogen in developing countries was also highlighted and discussed. This review provides a comprehensive insight for further research on hydrogen production technology from an LCA perspective.