New natural gas facility converts cow poop to power

Facility is the equivalent of taking 25,000 cars off the road each year

By Kaitlin Washburn

In California’s ongoing effort to slow climate change, the state’s dairy industry is reckoning with the reality of how cow patties contribute to greenhouse gas emissions.

The industry contributes four percent of the state’s total emissions, and methane gas from cow manure makes up half that amount.

But a new facility run by Calgren Dairy Fuels and Southern California Gas Co. is flipping that script by capturing the methane and converting it to renewable gas. The hope is the natural gas plant will be the equivalent of taking 25,000 cars off the road.

At an event last Monday announcing the completion of the facility, Jeff Walker, vice president of customer solutions for SoCalGas, called it a big step toward the company’s goal of offering the cleanest natural gas in North America.

“Renewable natural gas is a ready, reliable and realistic way to reduce [greenhouse gas] emissions and pollution from heavy duty transportation and buildings and will help ensure that families and businesses have an affordable option for heating and cooking as California transitions to a clean energy future,” Walker said.

Located in Pixley, the plant is the first of its kind in California and by later this year is expected to become the largest biogas operation in the United States A similar facility exists in Indiana.

Currently, 14 dairies are partnered with Calgren, and the company plans to bring eight more on board by the end of the year.

In 2016, California passed legislation mandating that dairy farms cut their methane emissions 40 percent by 2030. California dairies emit 55 percent of the state’s total methane emissions.

Carbon dioxide and methane are two of the principal greenhouse gases. Methane is 28 percent more potent than carbon dioxide. The gas, however, only remains in the atmosphere for about a decade, while carbon dioxide’s lifespan lasts thousands of years.

This facility will eventually capture methane from the manure of 75,000 cows and prevent 130,000 tons of greenhouse gases from entering the atmosphere each year, which equals the emissions from 25,000 cars, said Walt Dwelle, the principal owner of Calgren Renewable Fuels.

The cow manure is put into a lagoon that acts as an anaerobic digester, which breaks down organic materials to produce biogas. Methane gas is generated through this process and then sent to the facility via a network of pipelines connecting participating dairies to the facility.

Once there, it is converted to renewable natural gas, which is injected into the SoCalGas pipeline. That gas will fuel ultra-low emissions trucks, generate clean electricity and heat homes and businesses throughout the state.

Renewable natural gas reduces climate pollution more than it emits as an energy source. Using natural gas also means that less diesel is used and fewer fossil fuels are burned.

At Monday’s event, SoCalGas gave Calgrens a $5 million incentive check to support the development of renewable energy projects.

The California Department of Agriculture partially funds dairy digesters throughout the state under California’s Dairy Digester Research and Development Program. There are currently 30 methane digesters in operation in California.

A facility like this is a big deal and will go a long way to reduce the state’s greenhouse gas emissions, said Dr. Frank Mitloehner, a professor and air quality extension specialist at the University of California, Davis.

“If we want to reduce 40 percent of cow manure methane within the next 11 years, we need to do something and quickly,” Mitloehner said.

Some argue that cows should be raised on pastures rather than farms, Mithoehner said. They believe that more methane gas is emitted when the cows’ manure is stored in lagoons on farms.

Mitloehner said raising cows pastures is unfeasible and doesn’t reduce greenhouse gas emissions. Methane is produced by cows regardless of how they live.

The methane that is ultimately released into the atmosphere via cow poop and burps is created by microbes in the animals’ digestive systems. The microbes produce more methane from the grasses cows eat when they live on pastures, Mitlochner said. He added that cows living on pastures, rather than farms, produce one-third less milk.

“Everything should be considered, from environmental impacts to financial viability. If you can’t make a living, then your dairy won’t stay open,” Mitloehner said. “Especially in places like Tulare [County] where dairy is one of, if not the most, important economic aspects of your county. The goal should be to remain in business with the lowest environmental impact.”

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