Energize Weekly, June 6, 2018
The power sector’s consumption of fossil fuels dropped in 2017 to levels not seen since 1994, as a result of closing aging coal plants and adding more efficient natural gas turbines, according to the federal Energy Information Administration (EIA).
For the last four years, fossil fuel use has dropped steadily for the sector sliding to 22.5 quadrillion British thermal units (BTU) in 2017 from 25 quadrillion BTU in 2014.
“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 slightly offsetting increase in the use of natural gas,” EIA said. “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.”
Coal consumption in 2017 was at its lowest level since 1982 with about 30 coal-fired plants closing during the year. Petroleum consumption was at its lowest level since 1949.
Natural gas consumption in the sector has been on the rise as natural gas-fired plants have been added to the fleet. Almost 32 gigawatts (GW) of new electric generating capacity is set to come online in 2018—the most in a decade, the EIA said.
EIA’s January 2018 Short-Term Energy Outlook forecasts that natural gas will remain the primary source of electricity generation in the U.S. for at least the next two years, with the total share of electricity supplied by natural gas-fired power plants averaging 33 percent in 2018 and 34 percent in 2019—up from 32 percent in 2017.
Still, 2017 natural gas consumption was slightly lower than the record-high 2016 level.
In energy-equivalent terms, more coal was consumed in the power sector than natural gas in 2017—12.7 quads to 9.5 quads, the EIA said. Natural gas-fired power plants, however, produced more electricity than coal-fired plants.
A big reason for both the slow growth in natural gas consumption in the power sector and the larger share of generation lies with the increasing efficiency of new, combined-cycle natural gas-fired technology.
“As recently as 2000, natural gas-fired power plants were on average about as efficient as coal-fired plants,” the EIA said. “Since then, new natural gas-fired power plants have tended to use combined-cycle generators, which are more efficient because the waste heat from the gas turbine is routed to a nearby steam turbine that generates additional power.”
Combined-cycle units now compose most of the natural-gas fired generation capacity and by the end of 2018, combined-cycle plants may surpass conventional coal-fired plants, the EIA said.
More than 21 GW of new natural gas-fired capacity is set to be added in 2018, the most in a decade, representing two-thirds of all the new capacity for the year.
Meanwhile, about 1.5 GW of coal-fired capacity will close this year, more than double the closures in 2017, according to an analysis by the Institute for Energy Economics & Financial Analysis, a non-profit, foundation-funded group.
The technology is more efficient, leading the natural gas-fired generation’s weighted average efficiency of fossil fuel-fired electricity generation to improve. In 1994, fossil-fuel power plants required 10,400 BTUs of primary energy to produce each kilowatt-hour (kWh), and by 2017, that rate had fallen to 9,400 Btu/kWh.
