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Utilities Identified as Major Methane Leak Source, California Report Says

California's two major natural gas utilities are responsible for the bulk of methane leaks statewide, outpacing oil/natural gas activities in the state, which ranks third nationally in oil production, according to a new state report.

The report calculated that 6.6 Bcf escaped from utility facilities or those of their customers, more than twice the loss from the state's oil and gas wells.

The total calculated under the latest (2015) annual report mandated by a 2014 state law (SB 1371) is larger than estimates on the total volumes that escaped during the four-month Aliso Canyon underground gas storage well leak from late October 2015 through mid-February 2016.

Leaks in 2015 from the utilities "have the same climate impact as burning more than 1 billion gallons of gasoline," said blogger Amanda Johnson with the Environmental Defense Fund (EDF), which is carrying out anational initiative to rein in methane emissions from the oil/gas sector. Johnson calls California's level of leak volumes "a major environmental problem."

California's report is based on emissions data collected under SB 1371 and not previously tabulated.

Estimates are that 78% of the gas leaks occur at four sources: utility customer meter sets, utility metering/regulating stations, ungraded leaks, and intentional venting at locations like the state's 12 underground gas storage facilities, Aliso Canyon being the largest.

This new data will be used in response to another new law, SB 1383, mandating methane reduction goals, such as a 40% target for emissions reduction below 1990 levels by 2030. "The report highlights the ambitious goals set forth by California and [we are] enthusiastic about doing our part to help California and the larger global community address important changes needed to reduce carbon emissions," said a spokesperson for Pacific Gas and Electric Co. (PG&E).

"The emissions are likely to go up before they go down," said Johnson, citing the fact that leak detection and quantification technology required under SB 1371 are more advanced in finding leaks. It is expected that utilities will start more closely documenting leaks and total volumes of emissions, although her analysis of the report is somewhat critical of Southern California Gas Co.'s (SoCalGas) efforts, compared to the state's other huge gas utility, Pacific Gas and Electric Co.

EDF accuses SoCalGas of "dragging its feet," arguing with state regulators' recommended practices for leak detection and prevention measures. "These differences in utility commitment to reducing emissions may be softened by providing the public with an accurate and transparent report of emissions," Johnson said.

To the contrary, SoCalGas officials told NGIon Friday that they are championing "many new technologies that allow the company to detect and repair non-hazardous leaks more quickly than ever," and focusing on the state's largest sources of methane found in landfill and the agricultural (dairy cattle) sectors.

Last year joint work by the California Public Utilities Commission (CPUC) and the California Air Resources Board (CARB), along with utilities and stakeholders, developed a list of 26 best practices for utilities with a focus on five operating areas:

  • Transmission pipeline and metering/regulating station blowdowns;
  • Customer meters and U.S. Pipeline and Hazardous Materials Safety Administration "minor" leak guidelines;
  • Storage, such as control vents, leaks, blowdowns, compressors, casings and other leak sources;
  • Compressor stations, such as leaks from valves, connections, meters, vents, packing and blowdowns; and
  • Mitigation choices from a regulators' working group proposal.

CPUC and CARB staff late last year revised the 26 best practices to account for each gas utility's unique systems among other things.

"This information should be used by gas system operators to help determine where emission reductions can be achieved to meet the state's methane emission reduction goal, while maintaining the safe and reliable operation of the regulated gas storage and delivery systems," according to the report authors.

Nearly all (99.6%) of so-called graded leaks categorized according to their urgency with Grade 1 needing to be fixed immediately involve utility distribution mains and service pipelines. Just a fraction of a percent are transmission pipelines and services. For all leaks -- graded and ungraded -- that totaled 6.6 Bcf in 2015, excluding any volumes from the Aliso Canyon storage well leak, distribution and customer infrastructure accounted for 71% of the total volume; transmission/storage accounted for the rest.

"The vast majority of ungraded emissions (64%) come from the components and equipment found throughout the [natural gas] delivery system," the report concluded. "By parsing the emissions and identifying the volume of emissions and their sources, utilities can focus on the most cost-effective means to reduce emissions."

Ultimately, the report by the two state agencies' staffs concluded that today's added leak data should allow utilities "to address operating and maintenance practices and component designs and materials to facilitate emission reductions."

PG&E has reiterated its "strong support" for the state's goal for the 40% emissions reductions, the combination utility spokesperson said, adding that it has committed to being "one of the cleanest companies" in the nation. A year ago, PG&E joined the U.S. Environmental Protection Agency's methane challenge program as a founding member, pledging to reduce emissions from transmission blowdowns by 50%.

"PG&E’s gas R&D team is also leading the ongoing development of new technologies including our highly sensitivePicarro mobile methane detection vehicles, continuous methane detection laser and sensor technologies," the spokesperson said.

SoCalGas stressed that it has adopted some of the best practices developed by the statewide working group, and it has embraced various advanced technologies including: special fiber optic cable that detects methane leaks and third-party damage to pipelines; infrared “point” sensors that can detect leaks before they can be smelled by people; infrared cameras on newly installed pipelines; and drones and other methods of aerial surveys.

"SoCalGas is also working on ways to address large sources of methane emissions and turn them into renewable natural gas; 80% of methane emissions in California come from waste streams, like landfills and farms," a SoCalGas spokesperson said. "This wasted methane should be harnessed so that instead of contributing to climate change it can be distributed through existing natural gas pipeline infrastructures [for home, business and electric generation uses]."

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