California Air Resources Board

Senate Bill 1371 Natural Gas: Leakage Abatement mandates the California Public Utilities Commission (CPUC), in consultation with CARB, to adopt rules and procedures to reduce methane emissions from commission-regulated pipeline facilities.  CPUC, together with CARB, initiated the rule development process in January 2015.  In June 2017, CPUC approved the first phase decision (D.17-06-015), which established an emission target, in-line with CARB’s Short-Lived Climate Pollutant Reduction Strategy, to reduce methane emissions 40% by 2030.  The first phase decision also required gas corporations to implement 26 best practices (BPs) and submit biannual compliance plans, beginning in 2018, to help achieve the targeted emissions reduction goal. 

In August 2019, CPUC approved the second phase decision (D.19-08-020) that set a restriction on rate recovery for Pacific Gas and Electric and Southern California Gas beginning in 2025.  These utilities must show a reduction of 20% below 2015 level by 2025.

With industry input, CPUC and CARB developed reporting templates for the utilities to report annual leaks and emissions.  CPUC and CARB have prepared annual Joint Reports that analyzed the utilities’ data and estimated total emissions for 2015-2017.  The 2016 annual Joint Report showed total emissions were 6,601 MMscf in 2015 and established 2015 emissions as the baseline y for emission reductions.  The total annual emissions in 2016 and 2017 were 6,267 and 6,399 MMscf, respectively.

From 2015-2017, the system-wide leak rate remained constant at approximately 0.33% of the total annual volume of transmitted gas.  The 2019 Joint Report that analyzed 2018 emissions data has been finalized, but not yet posted online.  This Joint Report discusses the latest improvements utilities have implemented in surveying, recording, and repairing distribution mains and services pipelines.  In addition, utilities continue to refine the methodology to estimate emissions from the un-surveyed areas of the natural gas system. 

For more information, such as presentation slides, appendices for the data reporting, and the annual Joint Reports, visit the CPUC Methane Leak Proceeding (R.15-01-008).