The big picture greenhouse gas that everyone is aware of is carbon dioxide. Yet carbon trading companies are also eyeing up the potential of methane - 23 times or so more potent than CO2 and presumably, 23 times more valuable.

The coal industry has also noticed - coal and methane occur naturally together. Companies like Alkane Energy have a head start.

According to Evan Evans, vice president and director of engineering for the Boulder, Colo.-based Econergy International Corp, there may be ". . . an opportunity in Wyoming to generate new revenue streams in a carbon trading regime".