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Climate Legislation An Opportunity For Dairy Digesters, But Hurdles Remain

Kerry Klein/KVPR
The underground chamber below the white doors at this anaerobic digester in Pixley can hold over a million gallons of manure at a time. The manure cycles 21 days and is broken down into its component liquids, solids, and gases—including methane.";

A few weeks ago we told you about concerns within the dairy industry following the state’s most recent climate legislation. The new laws require livestock producers to cut methane emissions from manure by almost half before the year 2030. It seems a tall task, but a kind of facility that’s popular in Europe could help the California dairy industry meet those goals—if only it were easier to build here. FM89’s Kerry Klein brings us to Tulare County with more.

When it comes to how Governor Brown has influenced the dairy industry, Joey Airoso doesn’t mince words. “He's making it difficult for anybody to produce anything in this state,” says Airoso, a dairy producer in Pixley.

Credit Kerry Klein/KVPR
Cattle feed at the Airoso Dairy in Pixley.

He’s worried because, in order to keep up with methane restrictions, dairy producers may have to overhaul their manure management systems or make expensive renovations. “He's going to put people out of business,” says Airoso. “A lot of them.”

But there is a technology that could help dairy producers meet their methane goals, and an example of it is humming along just three miles away from Airoso’s farm in Pixley: an anaerobic digester. It’s a facility that takes in manure—a lot of it—and processes it in a way that recovers most of the methane and results in products like fuel and electricity. “We receive manure from about 1700 cows,” says Sarah Gonzales, a compliance officer at Calgren Renewable Fuels, the company that operates the Pixley digester. “Nothing gets wasted here. Nothing gets put in a dumpster or in a landfill.”

Anaerobic digestion is a technology that can dramatically cut emissions from dairies and potentially even bring in profit. Digesters reduce the need for manure lagoons that smell and release tons of greenhouse gases like methane. California’s even offering subsidies to help build them. So, together with recent legislation, you might think it’s a field day for digester operators—like Lyle Schlyer. He’s the president of Calgren Renewable Fuels. “I think, for us, it's a great opportunity, and we intend to try to take advantage of that,” says Schlyer.

Digesters are common in Europe – Germany alone has over 6,000. And yet, due to a host of regulatory, permitting and economic challenges, California only has 15. “California has, in our view, ideal circumstances for digesters,” says Schlyer—“and it has so few.”

To figure out why, I visit Calgren’s digester and take a tour with Sarah Gonzales. It does indoors what manure lagoons do out in the elements—it allows the manure to decompose—but, because it’s a closed system, it recovers most of the liquids, solids and gases that are produced. Digesters look like other industrial buildings – usually tall, round, with a dome or cone-shaped roof, and with lots of twisting, turning pipes.

Credit Kerry Klein/KVPR
Calgren Renewable Fuels compliance officer Sarah Gonzales touches the solids filtered out of manure and pasteurized to kill bacteria.

Gonzales says those 70,000 gallons of manure a day come from a neighboring dairy, and they spend about 21 days inside the digester. The water that’s extracted can be cleaned enough to be used again for irrigation. Solids can be filtered out into a fibrous material to be used as bedding for cattle. It’s brown and mossy looking—Gonzales rubs some between her fingers. “You can touch it with your bare hands,” she says, since it’s been pasteurized and bacteria have been killed. “You would want to wash your hands afterwards; it may have a little bit of a smell to it.”

But the most economical byproduct is the methane. “As it goes through this 21-day cycle, the manure and the bacteria, they create gas,” she says, pointing, “and the gas is then funneled out through this pipe up here.” Operators can use the gas to create electricity to sell back to the grid, or they can refine it and inject it into natural gas pipelines that run through the state.

It sounds like a win-win: produce milk, and save on manure and methane. So why doesn’t California have more of these? The first answer: the environmental permitting process can be grueling. Calgren officials tell me it took the state almost five years to greenlight their digester.

But the underlying problem appears to be economics. These facilities are expensive—they run at least a few million dollars each. The state offers building subsidies, though many claim they’re not enough.

Credit Kerry Klein/KVPR
When produced in a digester, methane is considered a “biogas.”

Then, there’s the price that utilities pay for the electricity from digesters. On principle, utilities want to pay as little as possible so they can charge rate payers as little as possible. So the cheapest energy sources—like natural gas and wind—drive the costs of electricity down.

“So, what's happening is, for a producer to do a digester, it's not necessarily anywhere close to the cheapest way of producing electricity,” says Sean Hurley, an agricultural production economist at Cal Poly San Luis Obispo. “From the standpoint of trying to compete against a dam or a nuclear facility for just the cost of production per kilowatt-hour, it can be a challenge.”

Many also blame low milk prices—California’s producers are paid some of the lowest rates for milk in the country. So could raising those prices help offset the costs of digesters? Not necessarily.

“I think it would open up a lot of worms in the market,” Hurley says. “So what happens? You raise prices, people get more profitable. Then what do they do? They increase the number of cows that they have, which drive the prices down.”

There’s another factor we haven’t yet considered: the consumer, and the prices they pay for milk.

Just like some shoppers pay more for organic milk, Hurley suggests, maybe they would do the same for milk that was associated with a digester. “The consumer is king and producers typically are going to give the consumer what they want,” he says.

So, when it comes to climate change and the future of agriculture, maybe we’re all in this together.

Kerry Klein is an award-winning reporter whose coverage of public health, air pollution, drinking water access and wildfires in the San Joaquin Valley has been featured on NPR, KQED, Science Friday and Kaiser Health News. Her work has earned numerous regional Edward R. Murrow and Golden Mike Awards and has been recognized by the Association of Health Care Journalists and Society of Environmental Journalists. Her podcast Escape From Mammoth Pool was named a podcast “listeners couldn’t get enough of in 2021” by the radio aggregator NPR One.
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