Cow Manure Is Being Turned Into Clean Energy

Methane is a source of revenue for cash-strapped farmers

6 May 2016

Cows might seem like harmless animals as they graze in fields, but their belching and flatulence are major contributors to the planet’s greenhouse gas problem. Emissions from an adult dairy cow can produce as much as 650 grams of methane per day, according to Science News. On average, a cow produces about 150 kilograms of methane every year. Considering there are about 971 million heads of cattle in the world, that’s a lot of gas.

“Cows in general are bad for the environment. They produce a lot of methane because of their biological processes, and methane is a greenhouse gas,” says Saad Ansari, cofounder and chief technical officer of Connecterra, a startup in Amsterdam that makes high-tech pedometers to track cows’ steps and monitor their health. Connecterra is one of the companies featured in my article “Connected Cattle: Wearables Are Changing the Dairy Industry.”

“Long term, methane’s not very good for the planet,” Ansari says, “and cows have a direct impact.”

The pressure is on for farmers to reduce their cattle’s methane emissions. The U.K. Environment, Food, and Rural Affairs Committee in April called on farmers to “step up action” to reduce methane emissions, and singled out the livestock industry, according to The Huffington Post.

“Whether through improved feed to cut methane emitted by cows or better manure-spreading techniques, all farmers need to minimize their impact on climate change,” the committee said.

More dairy farmers now are using technology to capture methane and turn it into clean energy—not to mention profits.

MAKING THE MOST OF MANURE

Biogas is made from methane plus other anaerobic digestion byproducts. Biogas systems collect manure and transport it to an anaerobic digester, typically a tank or covered pond. Anaerobic digestion is a biochemical process in which organic matter is decomposed by bacteria in the absence of oxygen. Digesters must be airtight for anaerobic digestion to occur. The bacteria decompose the manure, releasing gas. Anaerobic biodigesters convert the methane into natural gas, which is used to generate electricity. And farmers can sell local utilities the extra electricity their biogas systems generate.

The methane from this Florida dairy farm's biodigester produces enough electricity to power 425 homes. 

Germany has 6,800 biodigesters in operation. The United Kingdom has more than 1,800, and Italy has nearly 1,200, according to a report from the European Biomass Industry Association.

With about 250 digesters, the United States is trying to catch up, according to the U.S. Environmental Protection Agency. Manure accounts for roughly 10 percent of U.S. methane emissions. If 2,650 digesters were operating on large dairy farms, the agency estimates their combined capacity would handle more than 97 million metric tons of cow manure annually.

NEW REVENUE STREAMS

Germany and the United States are two countries that offer incentives to help cash-strapped farmers set up biodigester systems. Through the California Dairy Digester Research and Development Program, for example, the state Department of Food and Agriculture has committed US $11 million to help farmers install the systems.

Farms that become certified as renewable energy generators can sell electricity to local utilities. Companies such as Green Mountain Power, in Vermont, are tapping into farm-produced biogas and selling it to customers. The utility company’s Cow Power program helps Vermont dairy farmers purchase generators that run on methane from cow manure. That increases renewable energy in the region and helps farmers get into the electricity business.

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