U.S. natural gas output rises as methane emissions fall, pointing to pollution control gains
Energize Weekly, June 12, 2024
U.S. natural gas production rose by 40 percent between 2015 and 2020, while methane emissions from drilling and extraction fell by 37 percent – pointing to significant gains in pollution control, according to a report by Ceres and the Clean Air Task Force.
“This downward trend can in part be attributed to state and federal regulations that have been enacted to date,” the study, based on an analysis of Environmental Protection Agency (EPA) emissions data, said.
New federal methane standards and the forthcoming Waste Emissions Charge on excess methane emissions are expected to help drive sector emissions even lower, according to the two non-profit environmental groups.
Methane is 80 times a more potent greenhouse gas (GHG) over 30 years than carbon dioxide, the main greenhouse gas. Overall, industry GHG emissions, including carbon dioxide, fell only 14 percent.
The EPA data covered 298 oil and natural gas producers with the top 100 operators accounting for 91 percent of the energy production, 74 percent of the methane emissions, and 76 percent of total GHG emissions.
The top methane emitters were the Hilcorp Energy Co., Diversified Energy Co., Caerus Oil and Gas, ConocoPhillips, BKV Corporation, and ExxonMobil.
However, when ranked by “emission intensity,” the top emitters were smaller companies, including Iron Senergy Holding, Miller Energy Co., Utah Gas Corp, Trendwell Energy Corp., and Titan Rock Exploration & Production LLC.
“The methane emissions intensity of natural gas production and the GHG emissions intensity of oil and gas production varies dramatically across producers,” the report said. “Natural gas producers in the highest quartile of methane emissions intensity have an average emissions intensity that is over 32 times higher than natural gas producers in the lowest quartile of methane emissions intensity.”
The analysis used two measures of emissions intensity: the Natural Gas Sustainability Initiative (NGSI) protocol and a calculation of emission divided by oil and gas production.
The NGSI, developed by the Edison Electric Institute and American Gas Association, focuses on the natural gas value chain and calculates intensity as methane emissions assigned to natural gas on an energy basis divided by the total methane content of produced natural gas.
This metric, expressed as a percentage, enables investors and gas purchasers to evaluate the methane performance of the natural gas value chain separate from the oil value chain.
The second measure takes the GHG emissions from production operations, in kilograms of carbon dioxide equivalent (CO2e), and divides that by the total oil and gas produced, combined in barrels of oil equivalent (BOE), for a measure of kilograms of CO2e per BOE.
Pneumatic controllers, which open and close valves and equipment, were the largest source of total reported production-segment methane emissions, making up 67 percent of total reported methane emissions.
Fuel combustion equipment, such as engines and heaters, was the largest source of total reported production-segment CO2 emissions, accounting for 61 percent of total reported CO2 emissions.
“In oil-heavy basins, associated gas venting and flaring can be a significant contributor to GHG emissions,” the report said. In North Dakota’s Williston Basin, for example, flaring is responsible for 50 percent of total reported GHG emissions.
Total reported methane emissions have declined since 2019, primarily from a reduction of reported emissions from pneumatic controllers and equipment leaks. Total CO2 emissions have plateaued since 2020 as flaring emissions fall. but emissions from combustion equipment increase.
