From poop to power: How farms could double as energy production plants

Cow poop might not be the most desirable thing to have around the house, but new research out of the University of Waterloo in Canada suggests that manure could be used as a renewable energy source to help heat your home while reducing greenhouse gas emissions.

In a paper published in January in the International Journal of Energy Research, chemical engineer David Simakov and his team proposed a technology that can convert manure into natural gas with the potential to heat homes, power factories, and supplement diesel fuel.

“We have demonstrated the feasibility of making substitute natural gas from cow manure and water using renewable electricity for conversion process,” Simakov told Digital Trends. “The process avoids harmful greenhouse gas emissions from manure and reduces the use of fossil natural gas.”

The benefits of renewable natural gas are twofold, according to Simakov. For one, it’s biogenic, meaning it’s from a biological rather than fossil source, making it more easily replenished. It also doesn’t add more net carbon-dioxide to the atmosphere when it’s burned for heating.

The researchers developed a computer model of a 2,000-cow dairy farm that converts manure into biogas by starving it of oxygen. This biogas can be used to power generators, using 30 to 40 percent of its energy potential. But by feeding the biogas hydrogen gas (which the researchers suggest could be generated via wind or solar power) and running it through a catalytic converter, Simakov and his team hope to convert it to natural gas, utilizing most of its energy potential and significantly decreasing the greenhouse gas emissions associated with using manure as fertilizer.

Simakov said the less appealing parts of the process — that is, the handling of manure — can be completed at dairy farms, far from a potential consumer’s olfactory range. The researchers predict that this project could generate revenue through the sale of the biogas and carbon credits. The biogas can also be integrated into current natural gas pipeline infrastructures.

“Manure is converted at a farm and the on-site generated renewable gas is injected to the already-existing natural gas pipeline infrastructure replacing fossil natural gas,” Simakov said. “Renewable natural gas is fully interchangeable with fossil natural gas.”

The big challenge now rests in making the conversion process more efficient.

“The process of converting biogas generated from manure into renewable natural gas still requires a lot of engineering to make it highly efficient and low-cost, to improve the economics,” he said.