The average utilization rate, also known as the capacity factor, for the entire US fleet of combined-cycle natural gas turbine (CCGT) electric power plants has experienced an upward trend due to improvements in the operating efficiency of new CCGT units. The US Energy Information Administration (EIA) reported a notable increase in the CCGT capacity factor from 40% in 2008 to 57% in 2022.
Over this period, the enhanced efficiency of newer CCGT units has bolstered their competitiveness against both other fuel sources and older CCGT units. The EIA highlighted two pivotal factors influencing CCGT unit utilization: the efficiency of the generator and the delivered cost of natural gas.
The introduction of more advanced H- and J-class natural gas turbine technology in the mid-2010s has played a crucial role in augmenting the efficiency of newer natural gas-fired power plants. Lower natural gas prices have further contributed to increased capacity factors at these plants, rendering the electricity generated more cost-effective than that from alternative sources, such as coal-fired plants.
Annual average capacity factors for CCGT units experienced substantial growth in 2012 and 2015, coinciding with significant declines in the annual Henry Hub natural gas prices. Grid operators typically dispatch generators based on cost, with CCGT units constructed between 2010 and 2022 often enjoying the advantage of lower operating costs. Consequently, these newer units are dispatched more frequently compared to older CCGT power plants.
In 2022, CCGT units initiated between 2010 and 2022 demonstrated an average capacity factor of 64%, surpassing those commissioned between 2000 and 2009 (55%) and 1990 and 1999 (35%). The data reveals a shift in dispatch priority, favoring the lower operating costs of newer CCGT power plants.
Approximately half of the current CCGT capacity was constructed between 2000 and 2006, responding to power shortages in the late 1990s and coinciding with the introduction of more efficient F-class natural gas turbines. As these CCGT plants approach the two-decade mark, a potential decrease in capacity factors is anticipated due to aging units.
The increased efficiency of newer CCGT power plants is evident in lower heat rates, measuring the amount of fuel required to generate a unit of electricity. CCGT power plants commissioned between 2010 and 2022 boast the lowest average heat rate, standing at 6,960 British thermal units per kilowatt-hour (Btu/kWh) in 2022, representing a 7% reduction compared to units commissioned between 2000 and 2009.
Combined cycle plants have solidified their position as the largest source of electric generating capacity and electricity production in the US. In 2022, the EIA reported the commissioning of eight new natural gas-fired combined cycle plants, contributing 7,775MW of generating capacity to the US grid.
While this marks a substantial increase compared to the preceding two years, where 5,002MW and 3,578MW were added in 2020 and 2021, respectively, it falls short of the gains recorded from 2017 through 2019. The commissioning of new combined cycle capacity continues to shape the landscape of US electricity generation, reflecting both technological advancements and shifts in energy demand.