[general_re]

Cows produce so much methane that a tube inserted in the anus will support a continuously burning flame.

And you know this because...?

[Gumlegs]

It's how I heat my house.

[aruanan]

And you know this because...?

Because I listened to an NPR program about flatulence in which they interviewed some British researcher named Colin Leakey. Ha ha ha.

[Calvin Locke]

And you know this because...?

I used to live in a town that had a landfill. They had 3 "flares" going continuously to burn off the methane.

And yes, the waste company looked in to powering diesel generators, and it was not economically feasible.
The gas contained too few BTUs. I think a cubic foot of NG sold in the US has to contain a minimum of around 550-600 BTUs per foot3