The average monthly capacity factor for simple-cycle, natural gas turbine (SCGT) power plants in the United States has grown annually since 2020 according to the latest figures from the US Energy Information Administration. Average capacity factors exceeded 20% for two consecutive summer months in 2022 – the first time on record, to meet peak electricity demand, based on data from EIA’s ‘Electric Power Monthly’ report.
SCGT power plants typically operate year-round in the USA but are most active during the summer when electricity demand reaches its peak and varies the most. For the past five summers, SCGT power plants operated at a 17% average capacity factor from June through August. The average monthly capacity factor during the rest of the year fell to around 10% as a result of less electricity demand and more consistent wind-powered electricity generation.
SCGT power plants are the second-largest source of US natural gas-fired power generation, after combined-cycle (CCGT) power plants. SCGT power plants are less efficient than CCGT plants but grid operators can use them as fast response sources, now more needed as the share of electricity generation from intermittent renewables grows. They can also best provide grid support because they can produce electricity quickly and ramp down just as quickly. Other natural gas-fired electricity generators, such as CCGT or steam boiler plants, can take two to three times longer than SCGT power plants to start and ramp up to full load.
An estimated 2121 MW of new SCGT capacity entered service in 2021, and EIA expects another 1196 MW to have entered service in 2022. Texas accounted for nearly half of the 2021 and 2022 capacity additions because of its need for more fast-starting generating capacity. Texas is experiencing both rising power demand and greater variability in supply.