Controlling fugitive methane from natural gas infrastructure and quantifying the losses are a critical part of controlling greenhouse gas emissions, according to panelists at the National Association of Utility Regulatory Commissioners. It is an even bigger deal with the growing switch from coal-fired power and gasoline-powered vehicles to natural gas. Methane is a far more potent greenhouse gas than carbon dioxide and is estimated to be responsible for 25 percent of global warming. \u201cUtilities don\u2019t have solid numbers on the amount of leaks from their gas pipelines,\u201d said Mark Brownstein, Environment Defense Fund chief counsel, Nov. 18. The leak rate \u201cgoes to the heart of whether natural gas is a low-carbon alternative to coal and oil,\u201d Brownstein pointed out. He added that a leak rate of one percent is \u201cthe breakeven point for natural gas compared to conventional vehicles.\u201d The problem is wrapped up in the inability to quantify leaks, as well as prioritize repairs, which are both environmental and safety issues. Should all leaks be treated equally or ranked by size of leak, asked Hank Linginfelter, executive vice president, AGL Resources. \u201cShould dollars spent on revitalizing the infrastructure be spent on the biggest leaks, but that presumes you know where they are?\u201d Linginfelter added. He noted that multiple small leaks on a pipeline may reflect a greater safety threat than a large leak. At the same time, technology is lacking to distinguish between large and small leaks. There is only technology to identify, not quantify, leaks, noted Thomas Hutchins, KinderMorgan Natural Gas Pipelines\u2019 health & safety vice president. The California Air Resources Board proposed regulations to reduce methane emissions from oil and natural gas production, processing, transmission and storage. On Dec. 9, 2014, board staff are to present regulatory approaches, estimated cost impacts, emission estimates and an environmental analysis for the proposed regulation.