Despite emissions from intensive animal husbandry often being fingered as a cause of climate change, researchers have suggested a new way that manure could be a source of renewable power.
A team at the University of Waterloo in Ontario, Canada, is studying ways of extracting natural gas from bovine and porcine excretions.
This gas would otherwise be released into the atmosphere during decomposition or muck-spreading, contributing to global warming.
The research was published in the March issue of the International Journal of Energy Research.
The team are positively giddy with excitement, or possibly dizzy from huffing a little too much parfum de vache, suggesting poo-derived gas as a greener alternative to fossil fuels and a replacement for diesel.
"There are multiple ways we can benefit from this single approach," said David Simakov, a professor of chemical engineering at Waterloo. "The potential is huge."
The team built a computer model based on an actual 2,000-head dairy farm, which already converts manure into biogas using anaerobic digesters. Some of the gas is then burnt to generate electricity.
In the model, the team converted the biogas into natural gas. The process, called "methanation", mixes biogas with hydrogen and shoves the result through a catalyst to produce methane.
The process is well understood, but needs electricity to produce the required hydrogen.
The researchers suggest that the electricity could be produced by wind or solar power (an approach Reg readers will recognise).
The result would be a natural gas that offers all the potential energy of manure, but with a fraction of the greenhouse impact of simply using the fragrant stuff as fertiliser.
To make the jump from theory to reality, the boffins are seeking $5m for methanation equipment at the lucky dairy farm, an investment that would be repaid in five years. ®