On February 14th, EPA released its latest draft greenhouse gas inventory. It’s particularly timely because Congress is weighing whether to use the Congressional Review Act to overturn BLM’s venting and flaring rule, which is purported to reduce methane emissions from oil and natural gas production on federal public lands. The rule is highly controversial due to its hotly disputed cost calculations and shaky legal underpinnings.

So what does the inventory tell us about greenhouse gas emission trends? Overall U.S. greenhouse gas emissions declined by about 2.2% in 2015, reaching the lowest mark in 22 years. EPA attributes this decline to fuel switching from coal to natural gas electricity generation, reduced fuel consumption, decreased heating demand due to a warm winter in 2015, and greater energy efficiency.

EPA uses CO2-equivalents to compare methane to carbon dioxide emissions on an “apples to apples” basis. Methane represents just 12.1% of total U.S. greenhouse gas emissions, even taking into account its higher potency. The largest sources of methane emissions in order are agriculture, the oil and natural gas industry, landfills, and coal mining. In total, the oil and natural gas industry emitted 201.5 million tons of CO2-equivalents, which represents 3.1% of total U.S. greenhouse gas emissions.

BLM’s venting and flaring rule aims to reduce methane emissions from oil and natural gas well sites, even though emissions there are very low, in the range of 1.1% to 1.6%. So what does EPA have to say about those emissions?

Petroleum system emissions continue their successful long-term trends, declining 28.9% since 1990. From 2014 and 2015 alone, petroleum system emissions dropped 7.5%, “…primarily due to decreases in emissions from associated gas venting and flaring.” In other words, the BLM methane rule, which is largely focused on reducing venting and flaring, is already late to the party. Industry has been significantly reducing rates of venting and flaring in the absence of BLM’s rule.

Likewise, natural gas system emissions have declined 18.6%, “…largely due to a decrease in emissions from transmission, storage, and distribution.” Although EPA inventories petroleum and natural gas system emissions separately, the sectors largely overlap. When taken together, oil and natural gas industry emissions have dropped 21% since 1990.

In addition, natural gas enables huge reductions in the electricity sector where emissions are an order of magnitude higher. Overall the electricity sector accounts for 31% of total U.S. greenhouse gas emissions. Coal supplies 34% of total U.S. electricity but a disproportionate 70% of the electricity sector’s greenhouse gas emissions. On the other hand, natural gas supplies 32% of U.S. electricity but only 27% of sector emissions.

Methodology Adjustments

In addition to updating the inventory with the latest annual data, EPA makes revisions to its methods for calculating greenhouse gases. Both the petroleum and natural gas system categories were revised significantly in 2016, and then revised again in 2017. Western Energy Alliance disputed EPA’s upward revisions for oil and natural gas in the 2016 inventory, showing how they were based on inflated data.

To its credit, EPA admitted in this latest inventory that the previous inventory was in fact overstated. EPA reduced its estimates for the oil and natural gas industry to more accurate reflect emissions factors and equipment counts. While we feel vindicated in our criticism of EPA’s inflated 2016 inventory, the damage has been done. BLM’s venting and flaring rule was based on the flawed 2016 inventory, and therefore claims regarding the amount of emissions the rule will reduce are likewise inflated.

In summary, the oil and natural gas industry continues to reduce methane emissions both absolutely and relatively per unit of production. And increased natural gas usage is one of the major reasons the United States has reduced greenhouse gas emissions more than any other developed country. Industry has achieved this success in the absence of federal methane regulation, yet new federal methane rules like the BLM venting and flaring rule are based on inflated EPA emissions estimates. Congress should keep that in mind while deciding whether to overturn the BLM venting and flaring rule.

Kathleen Sgamma is the president of Western Energy Alliance. Ryan Streams is the Alliance’s manager of regulatory affairs. The Alliance represents the Western oil and natural gas industry and is a supporter of Western Wire.