Fuel Cells vs. Batteries

Hydrogen fuel cells lost the passenger car race not because the technology failed, but because the math did.

The previous lesson showed that fuel cell stacks convert ~60% of hydrogen's energy to electricity. But that number flatters hydrogen. The real contest is well-to-wheel efficiency: how much of your original energy source actually moves the vehicle.

For a battery-electric vehicle (BEV), the chain is: grid electricity → battery charging (~95% efficient) → discharge (~95%) → motor. Well-to-wheel efficiency: roughly 77%.

For a fuel cell vehicle (FCV) running on green hydrogen, the chain is: grid electricity → electrolysis (~70%) → compression (~90%) → fuel cell stack (~60%) → motor. Multiply those out.

Before you read further: what do you expect the well-to-wheel efficiency to be for hydrogen?

The answer is roughly 25-30%. That's a 2-3x gap in favor of batteries. To drive the same distance, a hydrogen vehicle requires 2-3 times as much electricity at the source. In an era when clean electricity is the scarce input, that gap is decisive for mass-market vehicles.

Batteries won passenger cars. But the story isn't over.

Where fuel cells still compete: The efficiency gap matters less when the alternative is diesel, not a battery. Long-haul trucking, maritime shipping, and aviation face energy density constraints that batteries don't solve. A hydrogen fuel cell semi-truck carries far more energy per kilogram than a battery pack of equivalent weight. Backup power applications care about long-duration storage and refuel time, not round-trip efficiency. Industrial heat processes need high-temperature fuel, not electrons.

Policy implication: hydrogen subsidies aimed at passenger vehicles are hard to justify on efficiency grounds. Hydrogen subsidies aimed at heavy transport and industrial decarbonization are a different argument entirely.

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