Mariana Franco, Ricardo Assunção, Rui Costa Neto
Aviation and shipping are among the most challenging sectors to decarbonize, and both batteries and hydrogen have limited feasibility as alternative energy sources in these transportation areas. In this context, e-fuels, produced from hydrogen and carbon or nitrogen, have emerged as a promising solution to emissions reductions. This review examines the main e-fuels mentioned when considering these sectors, namely e-methanol, e-ammonia, e-kerosene and e-diesel, and for each, their main production pathways are described, and an economic analysis is performed. Beyond this, this article investigates what legal frameworks are currently in place to promote the incorporation of e-fuels in aviation and shipping, and discusses the importance not only of these regulations, but also whether they are enough to sustainably encourage this transition.