The average utilization rate for the entire U.S. fleet of combined-cycle natural gas turbine electric power plants has risen as the operating efficiency of new CCGT units has improved, the U.S. Energy Information Administration reported on Nov. 20.
The CCGT capacity factor rose from 40% in 2008 to 57% in 2022. Increased efficiency improved the competitiveness of newer CCGT units against other fuel sources and older CCGT units, EIA said.
Two factors affect the utilization of a CCGT unit: the efficiency of the generator and the delivered cost of natural gas, EIA said.
More advanced H- and J-class natural gas turbine technology entered the market in the mid 2010s, increasing the efficiency of newer natural gas-fired power plants, EIA noted.
“Lower natural gas prices typically increase capacity factors at natural gas-fired power plants because the electricity generated is cheaper than from other sources, such as coal-fired plants,” the federal agency said.
In 2012 and 2015, annual average capacity factors of CCGT units increased by more than seven percentage points when the annual Henry Hub natural gas price declined, according to EIA.
“Grid operators generally dispatch generators sequentially from lowest to highest cost. Because CCGT units built between 2010 and 2022 typically have the lowest operating costs, they are dispatched more frequently compared with older CCGT power plants,” EIA said.
In 2022, the capacity factor of CCGT units that began operations between 2010 and 2022 averaged 64%, compared with 55% for those that began operations between 2000 and 2009 and 35% for units that began operations between 1990 and 1999.
About one-half of today's CCGT capacity was built between 2000 and 2006. This sudden increase in the number of CCGT plants was in response to power shortages that occurred in the late 1990s, coinciding with new and more efficient F-class natural gas turbines entering the market, EIA said.
“Now, many of these CCGT plants are about 20 years old, which could lead to lower capacity factors as the units age.”
Lower heat rates are the result of increased efficiency of newer CCGT power plants. CCGT power plants built between 2010 and 2022 have the lowest average heat rate among all CCGT plants, at 6,960 British thermal units per kilowatthour in 2022, which is 7% lower than units built between 2000 and 2009.
