Emission Trends in Petroleum Refineries

Reported emissions in the refineries sector remained relatively consistent from 2011 to 2019, followed by a drop in reported emissions in 2020. Prior to 2020, refinery emissions ranged from a minimum of 172.6 million metric tons (MMT) CO2e in 2012 to a maximum of 182.5 MMT CO2e in 2018. A slight decrease in emissions of 0.1% was observed in the 2011 (178.2 MMT CO2e) through 2019 (178.1 MMT CO2e) time series. Reported emissions decreased to 160.9 MMT CO2e in 2020, a decrease of 9.7% from 2019.

Historically, refinery emissions trends depend on the number of operating refineries, the operable capacity, and the production slate. With respect to these three factors, we note the number of reporting facilities decreased from 150 in 2011 to 140 in 2020 because some facilities closed and a few very small facilities were no longer required to report. [1] The COVID-19 pandemic created challenging market conditions for refinery operators and resulted in the closure of a handful of facilities. [2] The number of reporting facilities is expected to continue to decrease in 2021.

With respect to operable capacity, we found that overall operable capacity (measured in thousand barrels per calendar day [3]) increased by 5.2% from 2011 to 2020. This data demonstrates that the expanded production capacity at existing refineries more than offset production declines from refineries that closed.

Finally, finished motor gasoline, distillate fuel oil, and jet fuel are the predominant fuels produced by refineries. During 2020, there were observed changes to refinery production slates due to the COVID-19 pandemic. Notably, the demand for transportation fuels, specifically finished motor gasoline and jet fuel, significantly decreased in 2020. These reductions in demand resulted in a 13.4% decrease in refinery throughput (measured as gross input to refineries in thousand barrels per day [3]) as compared to 2019. To adjust for lower demand, refineries shifted the production mix at domestic refineries [4] and likely had operational changes such as idling units and units running below capacity. These changes in refinery operations appear to have decreased the efficiency of refinery processes, resulting in an increase in normalized emissions per gross input (metric tons CO2e per gross input to refineries in thousand barrels per day [3]) for 2020. In 2020, normalized emissions per gross input increased 4.3% as compared to 2019. The 2020 normalized emissions per gross input are inconsistent with the historical time series trend. Historically a reduction in normalized emissions per gross input was observed, reflecting efficiency projects undertaken by refineries including the use of flare gas recovery.

[1]  40 CFR §98.2(i)(1) and (2) describe provisions under which a facility may discontinue reporting.

[2] U.S. Energy Information Administration, Refinery closures decreased U.S. refinery capacity during 2020 (accessed September 20, 2021) at: https://www.eia.gov/todayinenergy/detail.php?id=48636  

[3]  U.S. Energy Information Administration, Refinery Utilization and Capacity (accessed September 16, 2021) at: http://www.eia.gov/dnav/pet/pet_pnp_unc_dcu_nus_a.htm.

[4] U.S. Energy Information Administration, Changing demand for petroleum products has led to operational changes at U.S. refineries (accessed September 20, 2021) at: https://www.eia.gov/todayinenergy/detail.php?id=44936   

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