California Biogas Quality Standards

In response to state legislation, the California PUC finalized quality standard for biogas. They prescribe acceptable concentration levels for 17 constituents of concern in biogas, including arsenic, p-dichlorobenzene, ethylbenzene, n-nitroso-din-propylamine, vinyl chloride, antimony, copper, hydrogen sulfide, lead, methacrolein, alkyl thiols, toluene, ammonia, biologicals, hydrogen, mercury, and siloxanes. In response to industry concerns about the testing protocol approved for siloxane, SB 840 was requiring a siloxane study to determine an appropriate maximum siloxane concentration allowed in biomethane. CCST completed its study and presented its findings, conclusions, and recommendations in a public workshop on June 11, 2018. In 2019, the CPUC approved D. 19-05-018 which directed the utilities to modify their pipeline interconnection tariffs to implement the procedures for reduced siloxane testing requirements.