This Yahoo Finance article highlights companies using hydrogen power, a long-term green power source:

“Hydrogen, the most common element in the universe, is all around us – highly reactive and non-polluting. When used as a power source in chemical fuel cells, the chief byproduct is simple water. Hydrogen-fueled power systems have the potential to replace a host of combustion engine applications and vehicles.”

Read more at: “The Future of Hydrogen Power Is Here — and These Stocks Are Leading the Charge“