Strong EPA methane rule required to fully realize Clean Power Plan benefits

Within the past month, the U.S. Environmental Protection Agency unveiled two major initiatives intended to meaningfully cut our nation’s contributions to climate change. The Clean Power Plan aims to reduce greenhouse gas (GHG) emissions from the power sector by nearly one-third from 2005 levels by 2030. The proposed Methane Pollution Standard will contribute to the administration’s target of 40-45 percent reductions in methane emissions from the oil and gas sector. While each of these initiatives has received its own praise and skepticism, conversations have not touched on the importance of how they interconnect. While a rapid transition to clean, renewable energy is the fastest way to achieve carbon reductions, given the Clean Power Plan’s reliance on natural gas to meet emission targets, effective design and implementation of the Methane Pollution Standard is critical to achieving power sector GHG emission reductions.

With last week’s release of draft methane regulations designed to reduce leakage from new and modified oil and gas infrastructure, the EPA demonstrated strong potential for meaningful climate action. Methane is a very powerful greenhouse gas – shorter-lived than carbon dioxide, but over 80 times as strong in the short term. With record global temperatures this year and faster than anticipated sea level rise and loss of Arctic ice, curbing GHG pollutants as soon as possible is increasingly important to protect our nation and the global community.

{mosads}The final Clean Power Plan projects that natural gas fuel switching will largely be responsible for reducing GHG emissions by 32 percent from the power sector. These reductions are based, in part, on the nearly 50 percent increase in gas generation from 2005 to 2014, as well as an additional projected 20 percent growth in gas generation by 2030. The assumption that displacing coal with increased natural gas consumption will lead to a reduction in overall GHG emissions is predicated on future actual reductions in methane leakage across the entire natural gas lifecycle, which requires a strong set of methane regulations.

Methane can leak across all components of the natural gas system, from production and storage to distribution to homes and businesses. The EPA estimates current leakage rates around 1.5 percent, far below estimates found in the majority of recent field measurements published in scientific literature. While exact leakage rates are uncertain, recent studies have typically found upstream leakage rates of 0.42 percent to 8 percent. Science shows that leakage rates of greater than 2.8 percent dramatically erode the near-term climate benefit of switching from coal to natural gas. But lower levels of methane leakage also significantly contribute to the dangers of climate change.

Furthermore, the EPA’s Clean Power Plan employs an outdated 100-year methane global warming potential (GWP) of 25 to calculate its emission reductions. This number, which compares atmospheric heat trapped by methane relative to carbon dioxide, is now out of date and far below the most recent IPCC climate consensus of 36 GWP. Further, methane’s near term warming contribution is even stronger. Despite this, the EPA omits the most up-to-date IPCC consensus on the 20-year GWP of 87.  Accurate baseline emission estimates and GWPs are critical for effective implementation of both the Clean Power Plan and Methane Pollution Standard. 

The EPA proposed methane rule is the first federal-level attempt to reduce upstream methane emissions from the oil and gas sector and should be applauded. However, shortfalls in the current version of the rule could limit its effectiveness. In addition to setting a baseline using potentially inaccurate leakage rates, the rule only applies to new oil and gas wells, leaving an estimated 90 percent of oil and gas sector emissions in 2018 unregulated, according to a recent ICF study. For methane regulations to be effective, the proposed rule should reflect the most up-to-date science on leakage rates, and planned rules that cover existing oil and gas operations must be rapidly introduced and implemented.

States have a lot of flexibility in crafting their own Clean Power Plan implementation plans. The best option for the climate and public health is for the power sector to shift away from natural gas as well as coal and move directly to renewable energy sources to achieve emissions reductions targets. As it stands, however, the final EPA methane standards can either enhance or inhibit the Clean Power Plan’s effectiveness in reducing GHG emissions and the climate impact of natural gas used for heating, cooking and industry.  Accurately accounting for and reining in upstream methane emissions from both new and existing oil and gas wells will help ensure that the Administration’s Climate Action Plan achieves its intended climate benefits.

Krieger is director of the Renewable Energy Program at PSE Healthy Energy, an energy science and policy institute based in California and New York. Shonkoff is executive director of PSE Healthy Energy and a visiting scholar at the University of California, Berkeley.


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