The Fertilizer Institute (TFI) on June 12 told Green Markets that it questions the findings of a recently published report in the scientific journal Elementa, which states that methane emissions from ammonia fertilizer plants are “vastly “underreported and are 100 times greater than the fertilizer industry estimates.
Researchers from Cornell University and the environmental advocacy group Environmental Defense Fund (EDF) used a Google Street View car equipped with a high-precision methane sensor to monitor methane emissions from numerous ammonia fertilizer plants in the Midwest in 2016
The researchers said useful data to quantify “fugitive methane emissions” were collected at six of nine ammonia production facilities, including plants at Fort Dodge and Creston, Iowa; Beatrice, Neb.; Dodge City, Kan.; and Verdigris and Enid, Okla.
“Natural gas is largely methane, which molecule-per-molecule has a stronger global warming potential than carbon dioxide,” said John Albertson, co-author of the study and a professor of civil and environmental engineering at Cornell. “The presence of substantial emissions or leaks anywhere along the supply chain could make natural gas a more significant contributor to climate change than previously thought.”
The researchers said they discovered that, on average, 0.34 percent of the natural gas used in the plants is emitted to the atmosphere as methane. Scaling this rate from the six plants to the entire industry suggests total methane emissions of 28 gigagrams/year, which the report claims is 100 times higher than the industry’s self-reported estimate of 0.2 gigagrams/year, and also well above the EPA’s estimate of 8 gigagrams/year from all industrial processes in the U.S.
The report said when a concentrated methane plume was detected at each site, the emissions were measured through dozens of laps on public roads around the facilities. The report said these fugitive emissions were likely due to a number of factors, including incomplete chemical reactions during fertilizer production, incomplete fuel combustion, or leaks.
“We took one small industry that most people have never heard of and found that its methane emissions were three times higher than the EPA assumed was emitted by all industrial production in the U.S,” Albertson said. “It shows us that there’s a huge gap between a priori estimates and real-world measurements.”
But TFI told Green Markets that it questions whether the methane concentrations that were detected can be fairly attributed to the ammonia plants in question when the automobile-borne sensors were not in close proximity to those plants, and where there are other potential sources of emissions, including natural gas pipelines, natural gas metering stations, wetlands, water treatment ponds, oil and gas wells, injection sites, and other industrial locations that are registered EPA air emissions sources.
TFI also noted the “high stack heights” at ammonia production facilities, and questioned whether the ground-level methane detected in the study could be accurately sourced to the ammonia facilities, given the buoyancy effect of methane.
“The Fertilizer Institute and its ammonia-producing members deploy all available technologies and processes to ensure that fugitive methane emissions are kept to a minimum,” said Chris Glen, Director of Political Affairs and Communications for TFI. “For example, U.S. ammonia production facilities have procedures in place to quickly detect and remedy any potential leaks from facility equipment, including automated system monitoring equipment, human operators using mobile gas detectors, regular inspection of all facility areas, and aerial monitoring of facilities and facility-related emissions.”