Power-to-X and the Green Chemical Revolution: A Review on Sustainable Energy Carriers and Synthetic Fuels

This work presents a comprehensive and technically detailed assessment of power-to-X technologies as enablers of deep decarbonization in the hard-to-electrify industrial and transportation sectors. By systematically examining the interconnections between renewable electricity, green hydrogen, and the synthesis of carbon-neutral fuels and chemicals, this study advances the understanding of power-to-X as a cornerstone of the sustainable energy transition. The novelty of this work lies in the integration of power-to-gas, power-to-liquid, and power-to-chemicals pathways with emerging circular economy strategies, carbon capture, carbon utilization, and digitalization tools. Detailed analyses of electrolysis technologies, methanation, ammonia synthesis, methanol synthesis, and biomass-to-X routes are provided, along with their techno-economic and environmental implications. The findings underscore the critical role of green hydrogen and synthetic carriers in enabling sector coupling, long-term energy storage, and infrastructure reuse. Moreover, the study identifies key barriers to scalability, including material constraints, high capital costs, and infrastructural limitations.