A two-year project sponsored by the German Federal Ministry of Economics and Climate Protection has successfully concluded, presenting the results of a pioneering development project for hydrogen combustion engines. Mercedes-Benz Special Trucks and Mörtlbauer introduced their Unimog and Mörtlbauer prototypes powered by hydrogen combustion engines, showcasing the practicality and low emissions of this alternative drive system. The vehicles, equipped with modified medium-duty engines, have undergone extensive testing and application-specific trials, demonstrating their suitability for heavy work applications. The prototypes, capable of running on gaseous hydrogen, provide high power output comparable to diesel engines, ensuring reliable operation of auxiliary equipment. The successful partnership between industry and science partners in the research network has paved the way for future development towards series production of hydrogen combustion engines. The project highlights the importance of hydrogen technology in achieving emission-free driving and working, complementing the role of electric vehicles in sustainable transportation solutions.