Companies like long-term player Ballard Power Systems, Linde, UTC Power and Air Liquide (which has built 50 big hydrogen generators) have made this a big business.

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The company can also lean on a trade group, the U.S. Fuel Cell Council, whose members range from specialty companies like Fuel Cell Energy and Ballard Power Systems to giants like General Electric and United Technologies.

FORBES: Magazine Article

One popular fuel cell stock that Redstone is avoiding: Ballard Power Systems (nasdaq: BLDP - news - people ), which focuses on the automotive market and is the biggest company in the fuel cell business.

FORBES: Fueling Speculation