The refuelling hydrogen system of a Hyundai car.
The refuelling hydrogen system of a Hyundai car. - 
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The big news from the car shows in Tokyo and Los Angeles is that hydrogen-powered cars will be coming to the market in the coming months. The three largest Asian car manufacturers, Hyundai, Honda, and Toyota will all be introducing hydrogen powered cars soon. Toyota's model will resemble its popular Prius hybrid, but will contain a hydrogen-powered engine.

Unlike electric and hybrid electric cars, hydrogen vehicles can be refueled in about the same amount of time it takes to fill up a traditional car. But unlike those cars that run on fossil fuels, water vapor -- not pollution -- comes out the exhaust pipe in the back of the car.

That doesn't mean hydrogen cars are necessarily better for the environment. While hydrogen could be derived from greener sources in the future, right now it's mostly derived from cracking the hydrocarbons found in natural gas.