Not Just Cow Burps: More Stringent U.S. Oil & Natural Gas Methane Emissions Regulations

Abstract

Methane is 84-86 times more potent as a greenhouse gas (GHG) than an equal mass of carbon dioxide for the first 20 years after emission, and 28-34 times more potent over a century. U.S. climate policies are based on an old value of the 100-year global warming potential (GWP), which is 20% smaller, and do not adequately account for accelerated near-term warming caused by methane. As the dominant constituent of natural gas, methane is emitted directly into the atmosphere throughout natural gas development. The Clean Power Plan (CPP) and New Source Performance Standards (NSPS) were developed using EPA Greenhouse Gas Inventory (GHGI) estimates of fugitive methane emissions from oil and natural gas (O&G) operations. Recent studies show the GHGI significantly underestimates methane emissions, primarily because it underestimates rare large and ephemeral sources from existing O&G infrastructure. Given the rising importance of natural gas electricity generation, U.S. climate policies should reflect this research. In this study, after reviewing the latest research and policy developments relating to O&G methane emissions, I quantify the potential methane emissions that could be averted under various leakage monitoring regimes and by regulating emissions from existing O&G infrastructure. These directly address some of the major shortcomings of the NSPS and have the potential for GHG emissions reductions from the power sector as significant as the CPP.