Coal-Fired Power Plant Retirements in the U.S.

Davis, Holladay, and Sims summarize the history of U.S. coal-fired generator retirements over the last decade, describe planned future retirements, and forecast the remaining operating life for every operating coal-fired generator. Nearly one-third of the coal fleet retired during the 2010s and a quarter of the remaining capacity has announced plans to retire. They summarize the generator technology and location trends that are correlated with the observed retirements. The researchers then describe a theoretical model of the retirement decision coal generator owners face. Davis, Holladay, and Sims use retirements from the last decade to quantify the relationships in the model for retired plants. They use a machine learning algorithm to predict the decisions of active generators based on the relationship observed in retired units. Davis, Holladay, and Sims simulate future coal and electricity prices and identify which generators retire at what time in a business-as-usual policy scenario, under a coal subsidy, and under a carbon tax. Their model predicts that three-quarters of coal generation capacity will retire in the next twenty years, with most of that retirement concentrated in the next five years. Policy has limited ability to affect retirement times. A $20 per MWh electricity subsidy extends the average life of a generator by six years. A $51 per ton carbon tax brings forward retirement dates by about two years. In all scenarios, a handful of electricity generators remain on the grid beyond their twenty-year forecast horizon.