meta The U.S. dairy digester market is expanding, raising environmental concerns. :: The Bullvine - The Dairy Information You Want To Know When You Need It

The U.S. dairy digester market is expanding, raising environmental concerns.


A rising national market for the earnings of manure digesters—a technology created to reduce emissions and combat global warming—is raising concerns that the economic paybacks may undermine US climate change efforts.

Much of that worry is focused on California, which has given carbon credits for natural gas generated by dung digesters at dairies around the state. Already, such incentives seem to be compelling enough to spur the creation of digesters in other milk-producing states.

While California is largely seen as a climate leader, having enacted another headline-grabbing climate package this summer, it is also the heart of milk production in the United States. This presents a dilemma since cow dung produced by the state’s valuable dairy sector contributes significantly to methane emissions, a potent greenhouse gas.
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As California works to reduce emissions and address climate change, the state has set part of its hopes on the success of its dairy digester program. Digesters break down manure to extract methane and purify it into “renewable natural gas.” So far, the state has spent hundreds of millions of dollars on 117 digester projects.

Concern is being sown by the burgeoning national market in digesters and credits for the gas they generate. Some California towns and environmentalists are concerned that the projects would result in larger dairies, more cows, and more emissions. And, although the technology has the potential to play an essential part in combating climate change, experts believe more study is required to better understand the possible emissions from digesters and how their operation relates to a farm’s complicated nitrogen cycle.

“We believe that eliminating methane or halting methane emissions is vital to truly slowing the climatic consequences that are going to happen in the next two decades,” said Joe Rudek, an Environmental Defense Fund senior scientist who focuses on agricultural emissions. “However, we do not want to sacrifice local communities for the sake of global interests.”

Other states are now following California’s lead, constructing digesters to sell natural gas to a state program and even enacting legislation and incentive schemes to stimulate the technology’s adoption. This tendency may entice additional communities to weigh in on the digesters’ advantages. According to a U.S. Environmental Protection Agency report, the number of digesters operating in the United States has increased 1,320 percent since 2000.

In addition to providing incentives for digester construction, California enables the natural gas produced by them to be sold into and credited under the state’s Low Carbon Fuel Standard (LCFS) program. The program compensates operators for two benefits: the avoided emissions from methane collection and the reduced carbon intensity of the gas produced by the digesters in contrast to alternative fuel sources such as diesel.

Companies throughout the nation are gathering methane and transporting it westward since the state program enables digesters abroad to sell fuel to the state as long as it can be carried there via natural gas pipes. Currently, seven states are supplying natural gas derived from cow dung to California. Some businesses also transfer the power generated by digesters across state boundaries.

One Indiana firm transports gas generated by multiple dairies, processes it in an outlying area southeast of Chicago, and pipes it to California for use in automobiles. Natural gas from a collection of dairies is compressed and sent to California for use in transportation at a plant in West Texas.

Even Oregon dairies export some gas to California, despite the fact that the state has its own clean fuels program. The Oregon Department of Environmental Quality punished a dairy in Oregon that uses a digester and distributes natural gas to California last year for violating pollution limitations. Wisconsin, Idaho, Arizona, and Minnesota are also shipping manure-derived gas to the California market.

Digesters have been around for considerably longer in dairy-producing states than the ones adopted under California’s current scheme. Minnesota established a lending program for methane digesters in the late 1990s. However, since California allows dairy farmers and digester developers to earn extra carbon credits by selling natural gas, others are concerned that it would push dairies to expand and the market to expand throughout the nation.

Before California’s current digester program was established in 2005, Bob Jennings, the district director for Rep. Devin Nunes, a Republican who recently resigned from Congress to lead Trump Media & Technology Group, attended the dedication of one of the state’s early methane digester systems, at a 6,000-cow operation in Lindsay. It was partially supported by state money totaling $500,000. After the event, Jennings wrote to the dairy’s owner that the project may “be utilized as a model for dairies across not just the San Joaquin Valley, but also the whole country.”

Today, the two most active digester developers in California, Maas Energy and California Bioenergy, are targeting markets outside of the state.

Daryl Maas, the creator and CEO of Maas Energy, originally worked on digesters in Washington and Oregon before constructing his first in California, which began operations in 2013. The firm is actively developing and building projects in Nebraska, Wisconsin, and Texas. It also has digester operations in Arizona that generate power, but all of it is sent to California.

Maas’ company is based on California rules that encourage the use of digesters and the gas they generate.

“We’re looking at other states,” he said. “However, even if we develop in other states, the market we want to send our gas to is California,” he continued, citing the price of carbon credits.

CalBio arose with the enactment of the state’s AB32 legislation in 2006, which required reductions in greenhouse gas emissions. Aside from its California projects, the business has worked on a cluster of dairy digesters in South Dakota. It has a sales agent in Idaho and is looking to expand into the Texas market. “California has been dictating a lot of legislation around the nation,” says Neil Black, the company’s president and co-founder.

Unlike California’s digester incentive funds, which have mostly benefited projects associated with Maas Energy and CalBio, the low-carbon fuel standard credits are being distributed to a diverse group of developers and owners, some of which are significant oil and gas businesses. For example, a digester project in Kansas created in conjunction with the oil company Shell intends to benefit from California’s low carbon fuel requirement. Clean Energy Fuels, co-founded by oil and gas magnate T. Boone Pickens, is collaborating with BP on digesters in Iowa and South Dakota and has ambitious growth ambitions.

“There’s no lack of interest on the dairy side,” said Andrew Littlefair, president and CEO of Clean Energy Fuels, during an earnings call this year. “This is a national issue, and we’re speaking with dairymen and women around the country.” California and other jurisdictions purchase renewable natural gas from the firm.

The Washington State Department of Commerce will award roughly $1 million in funding for dairy digesters in 2020. The state will accept proposals for a $1.8 million pool of incentive funding for digester construction this autumn.

A regulation passed in Iowa in 2021 permitted dairies to construct anaerobic digesters and expand herd numbers provided the cows’ excrement was treated by the technology. Before the Act was passed, the state had just four digesters. As of December of last year, nine dairies have sought fresh licenses, with seven planning to add more cows to their facilities.

“There is a serious problem of spilling these days with California rules,” said Silvia Secchi, a professor in the University of Iowa’s department of geography and environmental sciences.

“These spillover effects in other states and other [agricultural] systems might have extremely large unexpected implications,” said Secchi, an expert on agriculture’s environmental impact. She sent comments to California air regulators this year, expressing alarm about the environmental repercussions of digester regulations spreading to neighbouring states like as Iowa.

Maas responds that he supports dairy farmers and that digesters help such farms by absorbing emissions that would otherwise be discharged. According to Black, president of California Bioenergy, it is inaccurate to imply that digesters generate air pollution and that their generation of natural gas helps to reduce pollution from diesel fuel.

However, Jeanne Merrill, senior policy advisor at the California Climate and Agriculture Network, an advocacy organization, believes that the potential of other states increasing herd numbers in order to secure state cash may result in “a perversion of California’s climate policies.” Merrill was a member of a working group created by California’s state government and regulators in 2017 to examine and recommend solutions to greenhouse gas emissions from cattle and dairy businesses.

The environmental organization Food & Water Watch has also questioned California’s dependence on digesters, as well as the technology’s growth throughout the nation. “This is occurring in Wisconsin and Minnesota,” said Tyler Lobdell, a group lawyer. “A business is now constructing digesters in Iowa with immediate intentions to make them viable off of California’s low-carbon field standard.”

Lobdell resides in southern Idaho, which is home to the majority of the state’s dairies and ranks third in the country in dairy output. Developers are looking for businesses where they can install digesters and profit from California subsidies, he says.

“As developers discover how much money there is to be earned, it will only get more acute,” Lobdell said.

Fellow Emma Merchant

Emma Foehringer Merchant is a journalist who has written about anything from natural catastrophes to wacky energy policies to air pollution. She has written on the environment and energy for The Boston Globe Magazine, The New Republic, Vice News, and Grist. Emma most recently covered sustainable energy as a staff writer for Greentech Media and assisted alums of that company in forming Canary Media. She is a graduate student at MIT’s Graduate Program in Science Writing and has a bachelor’s degree in environmental analysis from Pomona College, where she lived during the California drought while researching how climate change affects the state’s environment and people.


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