We’ve all heard of horsepower. Even automotive illiterates have a basic idea of what horsepower is.

And the larger the amount of horsepower a vehicle’s engine produces, the less fuel efficient it is likely to be. Less fuel efficiency equates to a greater drain on the world’s fossil fuel resources.

That’s where “cowpower” comes in. Conjuring a slightly comical picture, it is nonetheless a legitimate entry in the race to develop alternative energies and relieve some of the demand for petroleum.

The phrase “alternative energy“ normally brings to mind ethanol, the corn-based gasoline additive, or rooftop panels collecting solar energy, or desert wind farms.

But alternative energy has now found a home in the cow pastures of America, where, of all things, cow manure is being harvested to, and processed in, microbe-loaded “methane gas digesters”. The resulting “biomethane”, a colorless, odorless gas, could, as an alternative energy, replace natural gas in powering many of America’s public transportation vehicles.

Biomethane offers everything you’d want in an alternative energy. An estimate 8.5 million cows in the U.S. ensure a steady supply of its main ingredient; it can also be processed from the materials degrading at landfills.

Its use as a vehicle fuel need not be restricted to busses; Sweden, developing an alternative energy program, has, besides busses, 7,000 cars running on the product of seventeen biomethane plants.

The state of Vermont offers, for an extra $20 a month, biomethane from its dairy herds as the source of alternative energy electricity for some 400 environmentally-friendly customers.

And in Great Britain, inventor Harold Bate runs his car–which he operates at speeds up to 75 mph–with the methane from chicken droppings. He claims that the methane is also kinder to the vehicle, a 1953 Hillman, because it leaves no carbon buildup on his engine.

The touch of barnyard humor notwithstanding, there is a very good chance that further research will reduce the costs of producing biomethane as an alternative energy enough to make it commercially competitive on a wide scale.

Horsepower, cowpower, chickenpower, oh, my…