According to a new report from the U.S. Energy Information Administration (EIA), generating electricity has shifted from coal to natural gas, resulting in a 32 percent drop in CO2 emissions over the last 15 years.
EIA’s latest power sector emissions data shows carbon emissions continue to drop as more natural gas is used in the electricity sector. One key finding was that CO2 emissions from the electric power sector declined 32 percent between 2005 and 2019, as natural gas grew from 19 percent of total generation in 2005 to 38 percent in 2019.
In its “Short-term Energy Outlook,” the EIA said that while short-term increases in the price of natural gas may result in more coal-fired electricity generation, by 2022, both natural gas and coal will lose a portion of their shares of generation to renewables.
“Lower CO2 emissions have largely been a result of a shift from coal to natural gas in the electricity generation mix. In 2005, coal made up 50% of U.S. electricity generation; that share declined to 23% in 2019. Conversely, natural gas increased from 19% of total generation in 2005 to 38% in 2019,” the report said. “When generating electricity, coal emits significantly more CO2 than natural gas. In 2019, coal-fired generation produced 2,257 pounds of CO2 per megawatt-hour (MWh) of electricity. Natural gas-fired generation produced less than half that amount at 976 pounds of CO2/MWh.”
The use of renewables in electricity generation has also reduced emissions, the report said. According to the EIA, 9 percent of electricity generated in the U.S. in 2005 came from renewables, compared to 18 percent in 2019, largely due to growth in wind and solar generation. Nuclear generation, which has zero emissions, made up about 20 percent of American electricity generation in both 2005 and 2019.
While both the shift from coal to natural gas and the use of renewables contributed to CO2 emission reductions, the report said, it was the shift from coal to natural gas that had a larger effect. Of the 819 million metric ton decline in CO2 emissions from 2005 to 2019, 532 million metric tons of that decline (65 percent) were attributed to the shift from coal to natural gas, while 248 million metric tons, or 30 percent, of that was attributed to the increase in renewables.
EIA said that in the short term, as the rate of coal-to-gas switching reverses, it’s likely the declining CO2 emissions trend will change. The changes will depend first on the shares of coal and natural gas in electricity generation and on improvements in natural gas-fired generation efficiency.