First-of-its-kind interconnection system bridges dairy RNG and PG&E pipelines

In California, marking a first for Pacific Gas and Electric Company, renewable natural gas from Maas Energy’s facilities in Merced began flowing into PG&E’s gas transmission system through a “mid-market” third-party pipeline. This project effectively diverts methane that would have been released into the atmosphere from dairies in Merced County and converts it to RNG, a net ultra-low carbon emission fuel source.

Approximately 55 percent of California’s methane emissions come from dairies and livestock, according to the California Air Resources Board 2018 Greenhouse Gases Emissions Inventory.

This project produces RNG (also known as biomethane) by capturing methane at the source from 15 dairy farm partners in Merced County, and conducting a process called anaerobic digestion. From there, pipeline-ready RNG is transported to PG&E’s gas system via CEE’s pipeline where it is introduced at a receiver station near Panoche. The Maas Energy project, which includes gas production and cleaning equipment, as well as the interconnection facilities to move RNG from farms into the CEE and PG&E transmission pipelines, was funded in part by incentives from the CPUC under Senate Bill 1383 (Lara, 2016).

This project was primarily funded through the California Public Utilities Commission (CPUC) Dairy Biomethane Pilot Program, established as part of California’s strategy to reduce emissions of short-lived climate pollutants, including methane.