Uinta Basin VOC Emissions Half of Previous Estimates

by Ryan Streams, Regulatory Affairs Analyst on June 28, 2016 - 10:13am

Bonanza Creek Coal Fired Powerplant_UtahAfter years of collaboration with the Utah Division of Air Quality (UDAQ), Environmental Protection Agency (EPA) Region 8, and the Ute Indian Tribe, we have the first phase of the 2014 Uinta Basin Emissions Inventory. This emissions inventory provides the most accurate data on oil and natural gas emissions in the Uinta Basin. Western Energy Alliance worked tirelessly with UDAQ to provide the base data for the inventory, which UDAQ has compiled and just released.

The Uinta Basin is one of the few places in the United States known for having ozone levels that exceed federal air quality standards during the winter. Typically, high ozone readings occur in the summer in urban areas when high temperatures, intense summer sun, and ozone precursors like volatile organic compounds (VOCs) and nitrogen oxides (NOx) react in the atmosphere to form ground-level ozone. Winter ozone is a less studied phenomenon that occurs only under certain weather conditions of snow cover along with a temperature inversion. Elevated ozone levels were recorded in the winter of 2016, when oil and natural gas drilling activity was at a minimum, but not in 2014 when activity levels were at historic highs.  

Elevated wintertime ozone levels were first observed in the Uinta Basin in 2010.The State of Utah, National Oceanic and Atmospheric Administration (NOAA), EPA, Utah State University, and Uintah and Duchesne counties with support from Western Energy Alliance, conducted the three-year Uinta Basin Ozone Study to better understand winter ozone formation. Western Energy Alliance funded $2.625 million for the study with contributions from member companies. After the Alliance stepped up to help fund the study and provide data, we continued our collaboration on Uinta Basin air issues by assisting tribal, state, and federal governments with their efforts to develop a detailed emissions inventory.

Companies provided data on equipment count and design for tanks, separators, pneumatic controllers, and other pieces of oilfield equipment. UDAQ then collected the emissions data, factored in production composition data, and compiled them into a basin-wide snapshot of emissions. In all, the inventory captured data for over 96% of all wells in Uintah and Duchesne counties. The emissions inventory provides regulators with the best available scientific data necessary to conduct air quality modeling and develop effective control measures for improving air quality in the basin.

The emissions inventory shows basin-wide emissions of VOCs, thought by scientists to be the main drivers of ozone formation in the basin, are 49% lower than previous inventory estimates. Like in other oil and natural gas basins, the new inventory revealed primary VOCs have lower potency for driving ozone. That’s especially important because the oil and natural gas industry is the largest contributor of VOC emissions in the Uinta Basin. However, this downward revision of VOC emissions is yet another example of how industry has been able to reduce emissions while maintaining strong growth in oil and natural gas production. 

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