Fuel cells vs. batteries
These value propositions are less obvious in passenger cars today because fuel cells are not as efficient as batteries. A 100 kilowatt hours of AC electricity from grid delivers roughly 69 to 70 kwH of energy at the wheel of a BEV. For a fuel cell, that drops down to about 20 to 25 kwH of energy, Sinha said.

The reason is the energy conversion in fuel cells from hydrogen to electricity. Once the hydrogen is put in the tank, it is converted to electricity in the fuel cell stack, and then passed to the vehicle. The fuel cells stacks are only about 50% efficient, whereas batteries are about 80 to 85% efficient.
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