Energy Futures Research Center

The concept of hydrogen internal combustion engine vehicles (ICEVs) is not new, but has gained renewed interest lately, especially for heavy-duty trucks. Different from hydrogen fuel cell electric vehicles (FCEVs), which represent a novel zero-emission technology, hydrogen engines are modified conventional engines running on hydrogen fuel instead of gasoline or diesel. This study presents a comparative review of hydrogen engines and fuel cells, based on existing reports and discussions with industry. We consider aspects such as vehicle efficiency, greenhouse gas (GHG) and criteria pollutant emissions, hydrogen fuel purity, vehicle attributes, vehicle acquisition costs, total costs of ownership, and new policies. We find that hydrogen ICEVs offer some advantages and disadvantages: advantages include lower production cost and potentially greater reliability; disadvantages include potentially overall lower efficiency (and thus higher fuel cost) and lack of zero-vehicle-emission operation. While the technologies could be complementary (e.g., hydrogen ICEVs serving as a transition technology toward FCEVs), they also may compete, with success for hydrogen ICEVs resulting in setbacks for FCEV market success.