Hydrogen as the nexus of future sustainable transport and energy systems

Serving as a clean energy carrier, green hydrogen — hydrogen produced by the electrolysis of water — enables low-carbon transportation and facilitates the large-scale integration of intermittent renewable energy sources into the power grid, thereby enhancing system flexibility and decarbonization. Hydrogen fuel cell vehicles (HFCVs) are key to the integration of green hydrogen into the energy and transport systems. The adoption of HFCVs is being supported by advances in hydrogen production and fuel cell technologies, coupled with the development of hydrogen refuelling infrastructure. However, technological, economic and regulatory barriers to the growth of the hydrogen economy remain. This Review examines the progress and challenges in the integration of HFCVs into the energy and transport systems. We also consider challenges in scaling green hydrogen production using renewable energy and highlight the role of HFCVs in facilitating the integration of green hydrogen and renewable energy into the energy and transport systems. Finally, we provide a roadmap that outlines directions for research, policy and investment to overcome the obstacles to growing the hydrogen economy and harnessing hydrogen as a cornerstone of sustainable energy and transport systems.