Gas is de facto becoming the key balancing fuel in the US electric power sector, in particular due to decarbonization. Global Energy Monitor reports that from 2000 to 2023, the US decommissioned 160 GW of coal-fired power plants; over the same period, gas-burning TPP additions amounted to 418 GW. As a result, the share of coal-based generation in the United States plunged from 52% in 2000 to 16% in 2023, while the share of gas increased from 16% to 42%. This was accompanied by a drastic decline in nuclear reactor additions: from 1980 to 2000, 51 new US power units were connected to the grid and after 2000, only three reactors totaling 3.4 GW were put into operation (Watts Bar nuclear plant unit 2 in the state of Tennessee and plant Vogtle units 3 and 4 in the state of Georgia). The weight of nuclear power in total US energy output thus dropped from 20% in 2000 to 18% in 2023.
The expansion of gas-fired generation was associated with high availability of the power source: the Energy Institute estimates that US gas production doubled between 2000 and 2023 (from 518.6 bn to 1,035.3 bn m3). Another important factor was the advent of new technologies which made gas plants more efficient, as measured by the amount of heat required to produce 1 kilowatt hour (kWh) of electricity. For instance, B-, D-, and E-class gas turbines (following the US classification system) introduced in the 1990’s burned on average 8 thousand British thermal units (BTU) of heat energy, while the first generation F-class turbines (widely in use in the 2000’s) consumed 7.3 thousand BTU. For H- and J-class turbines in use since the 2010’s, the figure is 6.7 thousand BTU per 1 kWh.
Alongside energy efficiency, average gas turbine power output has been changing as well. The performance of B-, D-, and E-class units ranged from 80 to 110 megawatts (MW), first generation F-class units, from 160 to 190 MW and H- and J-class units, from 265 to 340 MW. Cost saving is achieved as average power output increases. According to EIA, the commissioning of 1 kilowatt (kW) of gas power capacity in the United States cost an average of $920 in 2021, compared with $1,428 per kW and $1,561 per 1 kW in the case of wind and solar generators, respectively (more recent data is unavailable).
