The role of hydrogen and fuel cells in the global energy system

Hydrogen technologies have experienced cycles of excessive expectations followed by disillusion. Nonetheless, a growing body of evidence suggests these technologies form an attractive option for the deep decarb onisation of global energy systems, and that recent improvements in their cost and performance point towards economic viability as well. This paper is a comprehensive review of the potential role that hydrogen could play in the provision of electricity, h eat, industry, transport and energy storage in a low - carbon energy system, and an assessment of the status of hydrogen in being able to fulfil that potential. The picture that emerges is one of qualified promise: hydrogen is well established in certain nic hes such as forklift trucks, while mainstream applications are now forthcoming. Hydrogen vehicles are available commercially in several countries, and 225,000 fuel cell home heating systems have been sold. This represents a step change from the situation of only five years ago. This review shows that challenges around cost and performance remain, and considerable improvements are still required for hydrogen to become truly competitive. But such competitiveness in the medium - term future no longer seems an unrealistic prospect, which fully justifies the growing interest and policy support for these technologies around the world

Power-to-X and power-to-power routes

The increasing dependence on a worldwide scale of the power generation sector on non-dispatchable renewable sources, such as wind or solar, is posing challenges to the electricity infrastructures that require flexibility solutions to keep the balance between power supply and demand. Flexible generation, energy storage, demand side response are among the several strategies pursued to increase the flexibility of electricity management in the presence of a large share of RES generation, but flexibility can also derive by the conversion of electricity to other energy commodities. Among the secondary energy carriers, electricity can be stored in the form of chemical potential following the so-called “Power-to-X” scheme. In this route, electricity is converted in energy carriers, such as hydrogen, that can be exploited not only for time-shifted power delivery (“X-to-Power” reverse scheme), but also employed to cover nonelectrical demand in different sectors, such as transportation, heating, and industry. This chapter provides a detailed description of the different routes in the Power-to-X scheme, highlighting the technologies, the benefits and services provided to the energy system, the strengths and criticality points, the possible applications of the output streams, and the lessons learned from projects and demonstrations worldwide

Future Trends

Considerable works have been conducted on the topic of ammonia and its production, storage, distribution, use and impacts (climate and public). It seems clear that the molecule will play a role in the near- and long-term future in supporting the decarbonization of our energy-hungry society. However, several questions arise from both these works and current support given to the transition of a zero-carbon economy via ammonia. Technical barriers, economic challenges and missing feasibility studies along with scepticism pose a threat to the concept. Therefore, the path to progress needs to be clear to efficiently enable the use of ammonia as a large contributor to tomorrow's worldwide economy, utilizing novel ideas to challenge old concepts. These future trends, mostly based on current works aforementioned in this book, will establish the scientific, industrial and governmental agendas that will foresee the creation of systems and techniques capable of using ammonia as a unique energy vector. Therefore, this chapter approaches many of these trends, seeding the grounds for ideas that will break through old stigmas and position ammonia in a leading role for a clean future