Introduction: the power-to-fuel concept

To replace fossil fuels with renewable energy sources (RESs), it is necessary to identify a versatile and efficient means of storage. Hydrogen is probably the best candidate and production and utilisation technologies are ready, whereas the solutions for its distribution and storage are still unsatisfactory. This obstacle can be overcome by resorting to the so-called power-to-fuel technologies. Hydrogen thus becomes an intermediary between RESs and the production of synthetic alternative fuels. The adoption of these technologies is very important since it immediately allows the development of a large infrastructure for the production of hydrogen, without having to wait for the advent of adequate solutions for distribution and storage. This introductory chapter lists the main options that will be developed in subsequent chapters.