Reported emissions from electricity production decreased significantly from 2011 to 2018, from 2,222 million metric tons (MMT) CO2e in 2011 to 1,815 MMT CO2e in 2018, a decrease of 18.3%. Reported emissions for 2017 declined by 4.1% from 2016. However, emissions increased by 0.8% in 2018, marking the first increase in emissions since 2014.
Over the time period of 2011 through 2018, national net generation of electricity remained fairly consistent with an increase of two percent.[1] Meanwhile, GHG emissions per unit electricity production by electric power facilities decreased from 539.7 to 442.6 MT CO2e per thousand megawatt-hours, an 18% drop. Several factors contributed to this reduction in emissions per unit of electricity produced including the increased use of renewable energy sources and more efficient natural gas combined-cycle generators.[2] In 2011, 42.3% of U.S. electricity was produced from coal and 24.7% from natural gas; but by 2018, 27.4% of electricity production was derived from coal and 35.1% from natural gas.[1] Electricity generated from renewable energy results in no greenhouse gas emissions from power plants; and generation from natural gas, particularly in combined-cycle generators, produces lower greenhouse gas emissions per unit of electricity produced than generation from coal.[3] The 2018 increase in emissions were primarily caused by continued economic growth and a warmer than normal summer that resulted in higher electricity usage for air conditioning.[4]
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[1] U.S. Energy Information Administration, Electric Power Monthly Table 1.1. Net Generation by Energy Source: Total (All Sectors), 2009-May 2019 (accessed July 28, 2019) at: https://www.eia.gov/electricity/monthly/epm_table_grapher.php?t=epmt_1_01
[2] Inventory of U.S. Greenhouse Gas Emissions and Sinks: 1990-2016. U.S. Environmental Protection Agency. April 12, 2018. EPA 430-R-18-003. Available at: https://www.epa.gov/ghgemissions/inventory-us-greenhouse-gas-emissions-and-sinks-1990-2016
[3] U.S. Department of Energy, Environment Baseline, Volume 1: Greenhouse Gas Emissions from the U.S. Power Sector. Available at: https://energy.gov/sites/prod/files/2017/01/f34/Environment Baseline Vol. 1--Greenhouse Gas Emissions from the U.S. Power Sector.pdf
[4] U.S. Department of Energy, Today in Energy, U.S. Energy-Related CO2 Emissions Increased in 2018 But Will Likely Fall in 2019 and 2020, January 28, 2019. Available at: https://www.eia.gov/todayinenergy/detail.php?id=38133.