A new report issued by EPA in late April – an update to the national emissions inventory for greenhouse gases – continues to highlight the oil and gas sector’s role as the country’s top industrial source of methane pollution and one of the top industrial sources of greenhouse gases overall. Moreover, while the update shows a net reduction in methane emissions from the sector relative to EPA's previous understanding, there are many reasons to believe EPA’s new numbers underestimate the real extent of the climate problem from oil and gas development.
Methane is a highly potent heat-trapping pollutant that the oil and gas industry vents and leaks from equipment and operations throughout the sector’s exploration, production, transmission, and distribution phases. In particular, hydraulic fracturing – a relatively new and highly controversial method for extracting oil as well as natural gas – poses risks to water resources and results in far more upfront methane released than traditional drilling methods.
Much debate has centered on exactly how much methane pollution the oil and gas sector emits, and thus how natural gas lines up versus coal in terms of its contribution to dangerous climate change. That debate has heightened since EPA began its long-overdue process of updating air pollution standards for the industry in 2011. The industry is now coming forward with data that it claims show oil and gas development isn’t as bad for the climate as we might have thought. But even if taken at face value, industry’s data still show that the sector is still a huge problem for our climate. As I wrote last summer, one major industry study that reduced estimates of methane from certain sources confirmed that the oil and gas sector is one of the country’s top climate polluters.
Now EPA has issued a revised accounting of the sector’s greenhouse gas emissions in its yearly report under the United Nations Climate Convention, known as the “Inventory of U.S. Greenhouse Gas Emissions and Sinks.” EPA did not conduct any new field or measurement studies of methane in constructing the new inventory numbers, but instead relied largely on the above-mentioned industry study, as well as other similar data sources and its own collection of greenhouse gas data under the separate Greenhouse Gas Reporting Rule Program, in revising its inventory of national emissions.
In the revised inventory, EPA’s overall figure for methane emissions from the oil and gas sector went down approximately 30% from the prior year’s inventory. Recent suggestions that this reduction means we no longer need to worry about methane from oil and gas, however, are dead wrong. Here’s why:
- EPA’s current inventory is incomplete and continues to omit significant sources of methane pollution from the oil and gas sector. EPA based the present revision in the sector’s emissions estimate primarily on changes to a single source category known as liquids unloading*, without adequately accounting for other potentially significant sources of methane. For instance, the inventory does not fully account for the huge uptick in the number of new hydraulically fractured wells (a point I noted this summer with respect to the industry study) or completions of hydraulically fractured oil wells (a significant source of methane as EPA acknowledged in issuing standards for a North Dakota reservation last year, but which is not accounted for in the inventory).
- The revisions do not reflect or explain exceedingly high rates of methane pollution documented in studies by other federal agencies. The data relied upon by EPA in the inventory revision do not cover every source in the sector or every sub-region of oil and gas development, nor do they reflect a representative sample of all sources and areas. As such, they do not explain or account for the shockingly high rates of methane pollution in certain areas documented in field studies such as that by the National Oceanic and Atmospheric Administration.
- Methane is a more potent greenhouse gas than EPA has previously recognized. The figures in EPA’s revised inventory use the old value for methane’s “global warming potential” (GWP) – 21. EPA recently proposed to update methane’s GWP from 21 to 25. In other words, EPA will consider each ton of methane to have under 20% more warming force relative to a ton of CO2 than under the agency’s old and dated accounting system. And there is reason to believe methane’s global warming potential is even higher.
- The oil and gas sector still ranks as the nation’s top source of industrial methane pollution and among the top three industrial categories of all greenhouse gases. Even at the reduced methane emission estimates in EPA’s new inventory, the oil and gas sector continues to rank as the nation’s top industrial source of methane at more than 176 million tons of carbon-dioxide equivalent in methane (see the inventory’s Executive Summary, Table ES-8). Counting the oil and gas sector’s carbon dioxide emissions as well as its methane, the sector ranks among the top three industrial sources of greenhouse gases, at just under 210 million tons of total carbon dioxide-equivalent pollution (see the Energy section of the inventory, Table 3-1). (Power plants are the top heat-trapping polluter, and the oil and gas sector stands in a virtual tie with the nation’s petroleum refineries.)
Fortunately, cost-effective controls are available for reducing the sector’s methane. As my colleague and I have written, many of these technologies actually save industry money. In fact, oil and gas companies can reduce methane emissions by 80% and generate $2 billion annually through implementing affordable and available technologies to reduce venting, fix leaks and minimize other waste throughout the chain. Yet, these technologies are not being fully deployed by industry. Given all of the ongoing concerns about this potent climate change pollutant and the industry’s enormous contribution to its emission—that has to change.
So in sum, while we may still not know the exact amount of climate pollution coming from the oil and gas sector, we do know that the sector is a major contributor to global warming and should stay at the top of the priority list for mandatory clean-up.
*Liquids build up in wells during a well’s production phase, slowing or eventually stopping production. During removal of the liquids, wells can vent significant amounts of methane and other harmful air pollutants if not properly controlled. Notably, the inventory revision does not require any change in EPA’s recent control standards for the industry, as EPA did not include a requirement for liquids unloading.