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SoCalGas and Calgren expand US dairy waste-to-biogas project

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Southern California Gas (SoCalGas) and Calgren Dairy Fuels have announced that four additional dairy farms have started sending manure-derived methane to Calgren’s biogas operation in Pixley, California. Calgren processes the methane into high-quality renewable natural gas (RNG) before it is injected into SoCalGas’ system.

The Calgren biogas facility now collects methane from more than 66,000 cows at 10 local dairy farms. The additional four farms that have joined the project are expected to almost double the amount of RNG produced at the plant, helping to reduce greenhouse gas (GHG) emissions and displace traditional natural gas.

Calgren joined forces with Maas Energy Works to develop the four new dairy digesters as well as the six previous digesters that have been operational since 2018. Sharon Tomkins, SoCalGas vice-president and chief environmental officer, said: “Over the last five years, renewable natural gas use in the transportation sector has grown by almost 600%. We’re looking to build on that success by delivering more renewable energy options to our customers, including renewable natural gas produced at farms, hydrogen made from surplus solar energy, and advanced fuel cell systems that can provide energy in extreme weather events.

“Each of these technologies will be essential to promoting the long-term reliability of our energy systems and to meeting California’s ambitious climate goals affordably.”

According to SoCalGas, more than 80% of all methane emissions in California come from organic sources like wastewater treatment plants, landfills, food and green waste and farms. In California, a 2016 law requires a 40% reduction in methane emissions from waste sources such as landfills and dairies, with provisions to deliver that energy to customers. The law is expected to boost the supply of RNG.

“Calgren is leading efforts in California on this front, working with both dairies and SoCalGas to mitigate emissions,” said Lyle Schlyer, president of Calgren Renewable Fuels. “This facility alone will eventually capture methane produced from the manure of more than 75,000 cows, preventing about 130,000 tonnes of GHG emissions from entering the atmosphere each year, the equivalent of taking more than 25,000 passenger cars off the road annually.”