The hydrogen-opposed piston engine, developed in partnership with Achates Power and Argonne National Laboratory, is a groundbreaking innovation in green mobility. This engine, reminiscent of the first steam engines, operates using hydrogen as fuel, resulting in only water emissions and serving as an eco-friendly alternative to traditional internal combustion engines. The unique design of the engine features two pistons moving towards each other in each cylinder to compress hydrogen gas for combustion. This arrangement leads to a more compact combustion chamber, reducing heat loss and increasing thermal efficiency. By eliminating the need for components like cylinder heads and camshafts, the engine becomes lighter, more fuel-efficient, and more powerful. One of the standout features of this engine is its remarkable thermal efficiency, exceeding 50%, higher than diesel engines. This efficiency, combined with nearly zero emissions, makes the hydrogen-opposed piston engine well-suited for heavy-duty vehicles and provides a promising solution for the decarbonization of transportation. While electric vehicles have made strides in the automotive industry, the hydrogen engine offers a compelling alternative, especially for heavy-duty applications. This engine has undergone testing to validate its durability and efficiency, paving the way for hydrogen to become a viable fuel source in various industries. The hydrogen-opposed piston engine represents a blend of traditional steam power and modern hydrogen technology, offering a glimpse into the future of emissionless, highly efficient engines. As efforts continue to refine this technology, there is a significant potential for this engine to drive a transformation in the transportation sector, presenting a sustainable and innovative solution for the challenges of today and tomorrow.