Since 2010, utilities have retired or announced the closure of more than 500 coal-fired power plants in the U.S. This has taken more than 100GW of coal-fired generating capacity out of the American electricity mix.
About one-fifth of those closures were facilities either converted to or replaced by natural gas-fired plants, according to a new report from the U.S. Energy Information Administration.
The EIA’s data shows that 121 U.S. coal-fired power plants were repurposed to burn other types of fuel between 2011 and 2019. More than 100 retired plants were converted or replaced by gas-fired generation, representing close to 30GW of replacement capacity.
The decision for plants to switch from coal to natural gas was driven by stricter emission standards, low natural gas prices and more efficient new natural gas turbine technology, according to the EIA.
Combined-cycle gas turbine (CCGT) plants accounted for 15.3GW of that replacement. Those CCGT generating sites produced 94% more capacity than the comparable coal-fired power plants they replace, the EIA reported. Advanced turbine technology pushed the efficiency and output increases.
In other cases, utilities and plant owners opted to convert coal-fired boilers to gas-fired thermal operation. Of those coal-fired plants more than 50 years old, 86 converted the boilers to burn gas, representing 14.3GW of capacity.
The utility with the most conversions between 2011 and 2019 was Alabama Power, which converted 10 generators located at four coal plants in Alabama, totaling 1.9GW of capacity, according to the EIA. These conversions took place between 2015 and 2016, largely to comply with the Mercury and Air Toxics Standards (MATS) required by the U.S. Environmental Protection Agency.
As the U.S. coal-fired electric generation fleet continues to manage challenges from emission standards and low prices for natural gas, EIA expects more of these conversions to take place in the future, particularly in the midwest and southeast. EIA has been notified of eight planned NGCC projects, five of which are currently under construction, which will replace existing coal plants.
Natural gas fuels more than 35% of U.S. generating capacity, followed by coal at below 25% and nuclear at 20%. Renewables now account for nearly 20%, mostly from hydro, wind and solar.