Carbon dioxide emissions (CO2) in the U.S. electric power sector have fallen 28% since 2005 because of slower growth in electricity demand and changes in the types of fuels used to generate electricity, according to the U.S. Energy Information Administration. In 2017, CO2 emissions from the electric power sector were 1.744 billion metric tons, the lowest level since 1987.
Excluding the electric power sector, CO2 emissions from all other energy sectors fell by 5%. In six of the past 10 years, electricity demand has fallen as industrial demand decreased and residential and commercial demand has been flat. If electricity demand continued to rise at the average rate between 1996 and 2005, CO2 emissions in the U.S. power sector in 2017 would have been about 654 million metric tons more than 2017 levels. If the types of fuels used to generate electricity remained the same as in 2005, the CO2 emissions would have been another 645 million metric tons higher in 2017.
Natural gas-fired generation has displaced coal-fired and petroleum-fired generation, and renewable sources of electricity generation, such as wind and solar, have increased. The market has largely driven the substitution of natural gas for other fossil fuels as a result of increased supplies of lower-priced natural gas and the ease of adding natural gas-fired capacity. In 2016, natural gas generation surpassed coal as the largest source of electricity generation.
Since 2005, state polices and federal tax incentives have encouraged the adoption of renewables. In 2005, noncarbon sources accounted for 28% of the share of U.S. electricity generation. By 2017, the share had risen to 38%. Nearly all the growth was a result of renewables, such as wind and solar, while shares for other noncarbon sources, such as nuclear and hydroelectricity, remained flat.