Ripe for Retirement

The Union of Concerned Scientists identifies a range of 153 to 353 coal-fired generating units in the U.S. that are economically uncompetitive and should be retired. These units, totaling up to 59 GW of capacity, are typically older, underutilized, and lack modern pollution controls. The report argues that retiring these units, alongside 288 already scheduled for closure, would not jeopardize grid reliability and could reduce annual CO2 emissions by 245 to 410 million tons if replaced by natural gas, renewables, or energy efficiency.

• The analysis identifies between 153 and 353 coal-fired electric utility generating units as 'ripe for retirement' because they are economically uncompetitive compared to cleaner alternatives. These units represent 16.4 to 59.0 GW of generation capacity and accounted for 1.7 to 6.3 percent of total U.S. electricity used in 2009.
• The identified 'ripe-for-retirement' units are characterized as being older, less utilized, and more polluting than the general U.S. coal fleet. They average 45 years in age and operate at an average capacity factor of 47 percent, compared to 64 percent for the total U.S. coal fleet. Additionally, over 70 percent of these units lack at least three of the four major pollution control technologies for mercury, soot, sulfur dioxide, or nitrogen oxides.
• Retiring the identified units in addition to the 288 units already scheduled for closure (41.2 GW) would result in a combined 100.2 GW of potential retirements. This transition could reduce annual CO2 emissions by 245 million tons if replaced by natural gas, or up to 410 million tons if replaced by zero-emissions sources and energy efficiency, representing 9.8 to 16.4 percent of 2010 U.S. power sector emissions.
• The retirement of these coal units is deemed feasible without risking national electricity system reliability. The U.S. was projected to have 145 GW of excess capacity by 2014, and existing underutilized natural gas capacity, combined with projected gains from state renewable electricity and energy efficiency standards by 2020, could replace the lost generation.
• Geographically, the most vulnerable coal generators are concentrated in the eastern U.S., specifically the Southeast and Midwest. Georgia, Alabama, Tennessee, Florida, and Michigan are the top five states for ripe-for-retirement generators. The largest owners of these units include Southern Company, the Tennessee Valley Authority, Duke Energy, American Electric Power Company, and First Energy.
• Economic variables such as natural gas prices and carbon pricing significantly impact the number of units deemed uncompetitive. Low natural gas prices and the implementation of a $15 per ton price on CO2 emissions have the most dramatic effect on expanding the pool of coal generators ripe for retirement.

APA

Union of Concerned Scientists (n.d.). Ripe for Retirement. https://www.ucs.org/sites/default/files/2019-09/Ripe-for-Retirement-Executive-Summary.pdf

Chicago

Union of Concerned Scientists. Ripe for Retirement. n.d. https://www.ucs.org/sites/default/files/2019-09/Ripe-for-Retirement-Executive-Summary.pdf.

Wikipedia

{{cite report |author=Union of Concerned Scientists |title=Ripe for Retirement |url=https://www.ucs.org/sites/default/files/2019-09/Ripe-for-Retirement-Executive-Summary.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{unionofconcernedscientistsndripe, author = {{Union of Concerned Scientists}}, title = {{Ripe for Retirement}}, institution = {Union of Concerned Scientists}, url = {https://www.ucs.org/sites/default/files/2019-09/Ripe-for-Retirement-Executive-Summary.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }