There are two main ways hydrogen powers cars: through internal combustion engines that burn hydrogen or through fuel cells that react hydrogen with oxygen to produce electricity. BMW tested a hydrogen fuel cell car called the BMW7 in 2015 that could accelerate from 0-60 mph in 9.5 seconds. Hydrogen fuel cell cars have a hydrogen tank, fuel cells that generate power from hydrogen and oxygen, and a power control unit that regulates electricity flow. They have higher efficiencies than gas or hybrid cars and produce only water emissions. Major auto companies like Ford, Honda, BMW, and GM are working on hydrogen fuel cell vehicles to reduce fossil fuel usage and costs.