As cow manure decomposes, it releases methane, a powerful climate-warming gas.
But if the manure breaks down in a system called an anaerobic digester, the gas is captured and can be used to generate renewable energy.
For many farmers, though, investing in a digester seems out of reach.
“It’s been said that farms need to have about 500 cows or more to make a digester project cost-effective in the United States,” says Matt Steiman of Dickinson’s College Farm in central Pennsylvania. “The average dairy farm size in Pennsylvania is 85 cows.”
So Dickinson’s College Farm is exploring how anaerobic digestion can be cost-effective at a smaller scale.
Smaller, more affordable digesters are used in Europe.
With the support of an EPA grant, Steiman’s team is importing a digester that will process manure from about 150 cows, along with up to two tons of food waste a day.
And they’re analyzing how such an investment might work financially. For example, excess electricity produced by the system can be sold to the grid. And farmers could process food and animal waste from other businesses for a fee.
“We’re trying to kind of field test this technology here in the States and see how it pencils out,” Steiman says.
They plan to share what they learn so more farms can cut their methane emissions and create clean energy.
Reporting credit: Sarah Kennedy/ChavoBart Digital Media