Hydrogen as a fuel in transportation

Hydrogen has attracted fresh attention in recent decades as an alternative renewable and sustainable transportation fuel. Hydrogen can fuel conventional or hybridized power trains, through highly efficient and low emission hydrogen-fueled internal combustion engines (H₂ICE) and proton exchange membrane fuel cells (PEMFC). High capacity and cost-effective onboard vehicle hydrogen storage remains a major challenge, along with the affordability of building out a distributed hydrogen production, distribution, and fueling infrastructure. Current practice is to store hydrogen onboard vehicles as a compressed gas, cryogenic liquid, or in chemical form for conversion on demand. Recent hydrogen demonstrations and field trials have advanced the technology, lowered costs, and improved public perception.