Biomethane from cows. It had to happen, according to Planet Ark
Pacific Gas & Electric Co. said Thursday it will purchase natural gas from cow manure produced at dairy farms in California to fuel power plants. The utility, a subsidiary of PG&E Corp., will buy the gas from Environmental Power Corp., a renewable energy developer based in Portsmouth, New Hampshire
Cows do produce methane and along with other ruminants contribute around 20% to atmospheric greenhouse gasses, according the University of Manitoba.
It is in farmer's interest to minimise this because bovine flatulence contributes to a loss of energy from cattle feed.
It seems that cows burp about 280 liters per animal/day according to a website called Riverdeep.
River deep continues
burped methane is more difficult to collect, with the result that about six million metric tons of it float blissfully up into the atmosphere every year. And that's just from herds in the United States. (Worldwide, ruminant livestock — including cattle, sheep, goats, and buffalo — produces about 80 million metric tons of methane per year, accounting for 22% of anthropogenic methane emissions.)
At this point it would be chulish not to quote the site once more:
Because of the large quantity of gas generated, burping performs a vital biological function for the cow. You can ask students to consider what might happen if a cow were unable to rid itself of the excess gas. (There are various urban legends about exploding cows, but none that we could corroborate.) This provides an unusual context for thinking about Boyle's Law.
Something a little more solid later...