U.S. fossil fuel consumption in the electric power sector in 2017 hit its lowest level since 1994 falling to 22.38 quadrillion British thermal units (quads), the Energy Information Administration said Tuesday.
According to the recently released Monthly Energy Review, the highest level over the last decade was hit in 2007 with nearly 28.5 quads.
The declining trend in fossil fuel consumption by the power sector has been driven by a decrease in the use of coal and petroleum with a slight offsetting increase in the use of natural gas, the EIA noted.
"Changes in the fuel mix and improvements in electricity generating technology have also led the power sector to produce electricity while consuming fewer fossil fuels," it said.
In 2017, coal consumption by the electric power sector reached its lowest level since 1982, and petroleum consumption in the power sector was the lowest on record, based on data since 1949, according to the report.
Recent natural gas consumption in the power sector, on the other hand, has generally been on the rise, but 2017 consumption was slightly lower than the record-high 2016 level, the EIA said.
"In energy-equivalent terms, more coal was consumed in the power sector than natural gas in 2017, at 12.7 quads and 9.5 quads, respectively," it added.
However, in terms of electricity generation, natural gas-fired power plants in the electric power sector produced more electricity than coal-fired plants last year, at 31 percent and 30 of the U.S. total, respectively.
The EIA pointed out that as recently as 2000, natural gas-fired power plants were on average about as efficient as coal-fired plants, but had since then become more efficient thanks to combined-cycle generators as the waste heat from the gas turbine is routed to a nearby steam turbine that generates additional power.
"Combined-cycle units now make up most of the natural gas-fired electricity generation capacity. By the end of 2018, natural gas combined-cycle units may surpass conventional coal-fired power plants to become the most prevalent technology for generating electricity in the United States," it said.
As the natural gas-fired generation fleet has grown and become more efficient, the generation-weighted average efficiency of fossil fuel-fired electricity generation has also improved, according to the agency.
"In 1994, fossil fuel power plants required 10,400 British thermal units (Btu) of primary energy to produce each kilowatt-hour (kWh); by 2017 that rate had fallen to 9,400 Btu/kWh," it said.
These changes in energy consumption and efficiency have also affected carbon dioxide (CO2) emissions from the electric power sector, which in 2017 were the lowest since 1987, it added.
Because coal combustion is much more carbon intensive than natural gas combustion, CO2 emissions from coal were more than double those from natural gas in 2017, even though natural gas provided more electricity generation," it said.
By Hale Turkes