Energy from dairy cow manure? The idea has hit the big time in Stanislaus and Merced
PG&E is about to get some of its gas from the manure of tens of thousands of dairy cows in and near Stanislaus County.
Aemetis Inc. held a gathering Friday, June 10, at a new plant in Keyes that will process methane piped in from 60 dairy farms in the area.
The $380 million project will reduce climate-harming emissions for both PG&E and the farmers. The latter also will get modest payments from Aemetis, helpful in a business beset by tight profit margins.
Aemetis contractors will employ several hundred people as the company builds out the system by 2025. And it will add about 10 permanent workers to the 75 already at the Keyes site, which has made ethanol from corn since 2011.
“It helps PG&E on our climate goals and it helps dairies with new income streams,” said Janisse Quiñones, senior vice president for gas engineering at the utility. “You can’t beat that.”
Aemetis, based in Cupertino, has become a leader in agriculture-based solutions to the climate crisis. It also is converting part of the old Riverbank Army Ammunition Plant to make aviation fuel from old orchard trees that had been burned in the open. That operation could open in 2024.
Conventional natural gas is petroleum-based and emits some of the carbon dioxide that impacts climate change.
The Keyes plant will supply less than 1% of the total demand, but it will help the utility toward its goal of 15% renewable gas. PG&E plans to start using the Keyes supply the week of June 12, if testing goes well, Quiñones said. It has about 15 million gas customers from Shasta to Kern counties.
Forty miles of pipeline
The dairy farms are in southern Stanislaus and northern Merced counties. About half of the planned 40 miles of pipeline is in place so far.
Methane is an especially potent climate changer if it wafts from dairy manure lagoons into the sky. Farmers working with Aemetis have installed digesters, which are airtight tanks where bacteria break down the waste. State grants can cover part of the cost.
The methane goes through the pipes to the Keyes plant, where it is purified to PG&E gas standards. The remaining manure is mixed with water and applied to feed crops on the farms, a common practice carried out under state oversight.
The Aemetis project will enhance the image of the industry, said Paul Sousa, director of regulatory and environmental affairs for Western United Dairies, based in Modesto.
The milk is processed into cheese, yogurt, ice cream and many other items at plants employing several thousand people in the two counties.
“Companies are looking to promote products that have a positive carbon footprint, and they’re looking for dairies to contribute,” Sousa said.
Fiscalini Cheese Co. installed the first manure digester in Stanislaus County in 2008, providing a small amount of electricity to the Modesto Irrigation District.
Several years passed before another was built, but now digesters are popping up steadily. They number 185 in California, according to Dairy Cares, an industry group.
Sousa said stand-alone digesters have not penciled out for smaller farms with, say, 600 cows. That could change if they are part of a PG&E cluster.
Dissenting view on biogas
The digesters do not impress activists who have been critical of the dairy industry’s environmental record. They say the farms continue to emit odors and threaten groundwater.
This is summed up in an October 2019 blog post from Leadership Counsel for Justice & Accountability, which has four offices in the Central Valley:
“While large dairies are sickening local communities, the gas industry is promising that these same dairies are an appropriate source for ‘renewable’ energy ... Expanding the capture of methane for biogas means we will need even larger factory farms that put the health of local, often low-income communities, and communities of color, at greater risk.”
This story was originally published June 13, 2022 at 6:30 AM with the headline "Energy from dairy cow manure? The idea has hit the big time in Stanislaus and Merced."
