Around fifteen years ago, Sweden introduced the Volvo Flexifuel engine, a blend of petrol and bioethanol like E85 that promised efficiency and power. Despite its popularity, the technology faded, making way for the rise of hydrogen as the green fuel of the future. The Flexifuel engines in mid-2000s Volvos boasted impressive performance and eco-friendliness, but they struggled due to limited bioethanol infrastructure and competition from electric vehicles and hydrogen. Bioethanol, derived from renewable sources, offered reduced carbon emissions but faced challenges like lower energy efficiency and lack of widespread availability. In contrast, hydrogen emerges as a cleaner option, generating no direct exhaust emissions and aligning better with the move towards carbon-neutral products. The shift to hydrogen is backed by substantial investments in infrastructure globally. The Flexifuel experience underscores the importance of robust infrastructure, market support, and long-term industry and government backing for sustainable fuel success. As Sweden transitions from its environmentally friendly engine innovations to the hydrogen era, lessons from the Flexifuel era aim to ensure a more successful adoption of hydrogen as a mainstream fuel.