Check out (HRID) Hybrid fuels on nasdaq. This little company is a complete pure play on ethanol. They burn cow manture to create the energy needed to produce the ethanol and utilize the balance of the energy to produce electricty. Their technology will make ethanol at a substantial discount to the producers that are using natural gas for the production process.
Do a little research and I'm sure you'll find this story of interest.
Now if only they could train cows to use a toilet collecting the stuff may be economical. Why don't you try a realistic pure ethanol play like XTHN? Oh, sorry, that must not be the stock you're pumping.