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Brown Gold: the Great American Manure Rush Begins

On an early August afternoon at Pinnacle Dairy, a farm located near the middle of California’s long Central Valley, 1,300 Jersey cows idle in the shade of open-air barns. Above them whir fans the size of satellites, circulating a breeze as the temperature pushes 100F (38C). Underfoot, a wet layer of feces emits a thick stench that hangs in the air. Just a tad unpleasant, the smell represents a potential goldmine.

The energy industry is transforming mounds of manure into a lucrative “carbon negative fuel” capable of powering everything from municipal buses to cargo trucks. To do so, it’s turning to dairy farms, which offer a reliable, long-term supply of the material. Pinnacle is just one of hundreds across the state that have recently sold the rights to their manure to energy producers.

Communities around the world have long generated electricity from waste, but the past few years have seen a surge in public and private investment into poop-to-energy infrastructure in the US. Though so far concentrated in states with dominant dairy sectors, like California, Wisconsin and New York, Biden’s landmark climate law passed last summer stands to unleash additional billions to support further development nationwide. The sector’s boosters describe it as an elegant way to cut emissions from both livestock and transport; but critics worry that the nascent industry could raise more issues than it resolves by entrenching environmentally harmful practices.

Animal agriculture is the nation’s single biggest source of methane, a greenhouse gas that climate scientists call a “super pollutant” due to its high short-term warming potential. The gas is released from animals when they burp, and through the decomposition of manure when collected in open-air ponds, a common livestock industry practice.

But those emissions are also a potential moneymaker. Methane from animal waste can be purified into a product virtually indistinguishable from fossil fuel-based natural gas. Marketed as renewable natural gas (RNG), it has a unique profit-making edge: in addition to revenue from the sale of the gas itself, energy companies can now also earn handsome environmental subsidies for their role in keeping methane out of the atmosphere.

In early 2020, an energy firm called Aemetis inked a 20-year contract to capture methane from Pinnacle’s manure and turn it into RNG. Aemetis installed a digester on the dairy, which collects the farm’s waste in a concrete-lined pool and captures the gas it releases. The company plans to upgrade it into renewable natural gas at its nearby refining facility, before transporting it to gas stations across the state.

“This is something that’s going to be on every dairy in the future,” said Jessica Cardoso, project coordinator at Aemetis.

Cardoso was raised on a dairy farm in California but, growing up, had no idea about the potential of cow manure. She predicts that natural gas and dairy production will soon go hand in hand.

Over the past few years, energy giants like ShellBP and Chevron have all announced similar dairy industry partnerships. In California, the country’s top dairy-producing state, officials estimated that over a hundred publicly supported manure digesters were slated to go online by the end of last year. Less than a decade earlier, in comparison, just six such projects were in the works. Nationally, the number of planned and operational RNG production facilities at livestock and agricultural operations jumped by over 36% in 2021 compared to the year prior.