As the world transitions to cleaner energy solutions, understanding how fuel cells compare to traditional internal combustion engines (ICEs) is essential. While both systems can run on hydrogen-based fuels, they differ fundamentally in how they generate power and impact the environment.
This guide explores their similarities, key differences, and what the future may hold for each.
Similarities Between Fuel Cells and Internal Combustion Engines
Though built on different principles, fuel cells and ICEs share some structural and operational commonalities:
- Fuel Source:
Both systems use hydrogen-rich fuels, whether in pure hydrogen form (for fuel cells) or fossil fuels like gasoline (for ICEs). Some ICEs can also be adapted to run on hydrogen. - Oxidant Use:
Both use air as the oxidant, though the methods differ:- Fuel cells compress air via an external compressor.
- ICEs compress air internally via pistons.
- External Fuel Supply:
Fuel is supplied from external storage tanks in both systems, supporting long operational ranges. - Cooling Requirements:
Both require cooling systems to manage heat, although ICEs operate at higher temperatures than fuel cells.
Fundamental Differences: Reaction Type and Output
| Feature | Fuel Cells | Internal Combustion Engines (ICEs) |
| Reaction Type | Electrochemical reaction | Combustion (chemical burning) |
| Energy Output Form | Electrical energy | Mechanical energy (via pistons, crankshaft, etc.) |
| Device Type | Solid-state (main cell), low moving parts | Mechanical system with many moving components |
| Efficiency | Higher (especially in hybrid setups) | Lower, with energy loss as heat and friction |
| Emissions (on hydrogen) | Zero (if using pure hydrogen) | Nearly zero (if optimized for hydrogen) |
| Emissions (on fossil fuels) | Very low (fuel cells with reformate gas) | High (significant NOx, CO₂, and particulates) |
Emissions and Environmental Impact
Pollution depends heavily on the fuel type and reaction temperature:
- Fuel cells running on pure hydrogen produce only water vapor—a truly zero-emission option.
- Fuel cells using hydrogen-rich reformate may emit small amounts of pollutants.
- ICEs using hydrogen can be engineered to minimize harmful emissions, but:
- Those using conventional fossil fuels emit CO₂, NOx, and particulates, significantly contributing to air pollution.
Technology Snapshot: ICEVs vs. FCEVs vs. BEVs
| Characteristic | ICEV (Combustion) | FCEV (Fuel Cell) | BEV (Battery) |
| Fuel Type | Gasoline/Diesel | Hydrogen | Electricity |
| Emissions | High | Low to zero | Zero |
| Refueling/Charging Time | Short (~5 mins) | Short (~5 mins) | Long (30 mins to hours) |
| Range | High | High | Moderate |
| Efficiency | Low | Medium-High | High |
| Infrastructure Maturity | Established | Emerging | Growing |