RNG Now Flowing into SoCalGas Pipelines from Calgren Dairy Digester


Southern California Gas Co. and biogas producer Calgren Dairy Fuels have announced that renewable natural gas (RNG) produced at Calgren’s dairy digester facility in Pixley, Calif., is being injected into SoCalGas pipelines.

The project marks the first time that carbon-negative RNG produced from cow manure has been injected directly into SoCalGas’ natural gas system, according to the utility. In August 2018, SoCalGas began receiving RNG into its system from CR&R Inc.’s anaerobic digestion facility in Perris, Calif. The RNG from that digestion facility is already being used to fuel about 400 waste hauling trucks.

“Developing renewable natural gas is a smart and cost-effective solution to reducing greenhouse-gas (GHG) emissions from the transportation and building sectors,” says Sharon Tomkins, SoCalGas’s vice president for customer solutions and strategy. “Replacing just 16 to 20 percent of our traditional natural gas with renewable natural gas would reduce emissions equal to electrifying 100 percent of buildings in the state, but it would be two to three times more cost-effective. Moreover, the renewable natural gas solution does not require expensive appliance changeouts or costly new mandates.”

“We are proud of what we have accomplished here,” adds Lyle Schlyer, Calgren’s president. “The benefits of this partnership between dairy farmers, private industry and SoCalGas are numerous. We produce clean, renewable natural gas for use as a carbon-negative fuel, which benefits the local community through cleaner air and jobs.”

Calgren’s facility, known as a dairy digester pipeline cluster, will collect biogas from anaerobic digesters at 12 Tulare County dairies and then clean it to produce pipeline-quality RNG. This is the first such dairy digester pipeline cluster in California, and it is expected to be the largest dairy biogas operation in the U.S. when Calgren adds nine additional dairies later this year. The facility will capture the methane produced from the manure of more than 75,000 cows, preventing about 130,000 tons of GHG from entering the atmosphere each year – the equivalent of taking more than 25,000 passenger cars off the road for a year, says SoCalGas.

SoCalGas will be capable of adding up to 2.26 billion cubic feet of RNG each year to its pipeline system from the facility – which is enough to fuel more than 1,200 Class 8 heavy-duty trucks.

The Calgren project is partly funded under California’s Dairy Digester Research and Development Program, which aims to reduce GHG emissions from manure generated at state dairy farms. Calgren’s preference is to provide renewable fuel for existing compressed natural gas refuelers in California via SoCalGas’ pipeline system. However, the Calgren facility is also able to use the renewable gas to indirectly produce a high-octane gasoline additive or to be used in a new biodiesel plant that will come online midyear.

Already, more than 60% of natural gas trucks in California are fueled by renewable gas delivered by SoCalGas pipelines, the utility says.

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