New conversion kits have been developed globally to convert old diesel engines into hydrogen-powered vehicles, providing similar performance at lower fuel costs. The reason behind this development lies in the limitations of electric vehicles for heavy machinery like agricultural equipment and road rollers that require continuous energy usage. Mahle, a major automotive parts manufacturer, has introduced kits to easily convert diesel vehicles to run on hydrogen, promoting sustainability and engine durability. However, the lack of hydrogen infrastructure has hindered mass production of such conversion parts due to high fuel costs. Toyota has entered this market with a heavy-duty hydrogen fuel cell powertrain kit, partnering with Kenworth to develop the kit using eth FECV powertrain. These kits, equipped with hydrogen fuel stacks, battery packs, electric motors, transmission, and fuel tanks, have undergone extensive testing, such as a Los Angeles to Long Beach trip refueled by Shell. The societal benefits of these kits are significant, including zero emissions, greater energy efficiency, and reduced dependence on fossil fuels, thereby contributing to a greener and more sustainable future.