Compressed Natural Gas Motor Vehicle Fuels

Work Continues on Revisiting the CNG/LNG Specifications

Staff is currently examining two ongoing studies.  The first is the Effect of Natural Gas Fuel Composition on Vehicles study, which is being conducted by the University of California at Riverside.  This study is sponsored by ARB and the California Energy Commission (CEC) to review the emission effects that lower Methane Number and higher Wobbe Index gas supplies may have on light and heavy-duty engines.  The second is the Natural Gas Variability in California: Environmental Impacts and Device Performance study, which the Gas Technology Institute (GTI) is conducting.  This study is investigating the effects that changes in natural gas quality may have on emissions from residential appliances and commercial equipment.  We anticipate that these studies, along with additional information we are gathering in collaboration with the gas companies, air districts, and other stakeholders, will enable us to better evaluate alternatives to the current set of CNG motor vehicle fuel specifications in California.  We intend to schedule one or more public workshops in 2013 to discuss regulatory concepts and other proposals based on these developments; the goal would be to propose a rulemaking for our Board’s consideration in late 2013.