For those interested in The Big Necessity

If you've read or skimmed The Big Necessity or, alternatively, have read Charlotte MacLeod's mystery novels set at a fictional agricultural college which powers itself with a methane plant, you might be interested in this article from CNN on a farm producing power from the waste of its 600 cows:
http://www.cnn.com/2009/TECH/07/31/cow.power/index.html