But … how reliable is coal, actually? According to an analysis by the Environmental Defense Fund of data from the North American Electric Reliability Corporation, a nonprofit that oversees reliability standards for the grid, coal has the highest “equipment-related outage rate” — essentially, the percentage of time a generator isn’t working because of some kind of mechanical or other issue related to its physical structure — among coal, hydropower, natural gas, nuclear, and wind. Coal’s outage rate was over 12%. Wind’s was about 6.6%.
“When EDF’s team isolated just equipment-related outages, wind energy proved far more reliable than coal, which had the highest outage rate of any source NERC tracks,” EDF told me in an emailed statement.
Coal’s reliability has, in fact, been decreasing, Oliver Chapman, a research analyst at EDF, told me.
NERC has attributed this falling reliability to the changing role of coal in the energy system. Reliability “negatively correlates most strongly to capacity factor,” or how often the plant is running compared to its peak capacity. The data also “aligns with industry statements indicating that reduced investment in maintenance and abnormal cycling that are being adopted primarily in response to rapid changes in the resource mix are negatively impacting baseload coal unit performance.” In other words, coal is struggling to keep up with its changing role in the energy system. That’s due not just to the growth of solar and wind energy, which are inherently (but predictably) variable, but also to natural gas’s increasing prominence on the grid.
“When coal plants are having to be a bit more varied in their generation, we’re seeing that wear and tear of those plants is increasing,” Chapman said. “The assumption is that that’s only going to go up in future years.”
The issue for any plan to revitalize the coal industry, Chapman told me, is that the forces driving coal into this secondary role — namely the economics of running aging plants compared to natural gas and renewables — do not seem likely to reverse themselves any time soon.
The coal system has been beset by a number of high-profile outages recently, including at the largest new coal plant in the country, Sandy Creek in Texas, which could be offline until early 2027, according to the Texas energy market ERCOT and the Institute for Energy Economics and Financial Analysis.
In at least one case, coal’s reliability issues were cited as a reason to keep another coal generating unit open past its planned retirement date.
Last month, Colorado Representative Will Hurd wrote a letter to the Department of Energy asking for emergency action to keep Unit 2 of the Comanche coal plant in Pueblo, Colorado open past its scheduled retirement at the end of his year. Hurd cited “mechanical and regulatory constraints” for the larger Unit 3 as a justification for keeping Unit 2 open, to fill in the generation gap left by the larger unit. In a filing by Xcel and several Colorado state energy officials also requesting delaying the retirement of Unit 2, they disclosed that the larger Unit 3 “experienced an unplanned outage and is offline through at least June 2026.”
Nevertheless, the Trump administration has plans to keep decrepit, polluting coal plants open far beyond their closing dates.
- The U.S. Department of Energy’s efforts to prevent large fossil-fuel power plants from retiring could cost ratepayers about $3.1 billion a year in 2028, according to a report released Thursday by Earthjustice, the Environmental Defense Fund, the Natural Resources Defense Council and the Sierra Club.
- Grid Strategies used the cost of a dozen recent reliability-must-run contracts from around the U.S. — $89,315/MW-year — as a proxy for the estimated cost of keeping fossil plants open due to a DOE mandate. The states with the highest potential annual costs by 2029 for keeping power plants from retiring are California at $389 million; Texas, $183 million; Colorado, $178 million; Michigan, $171 million; Louisiana, $164 million; and Illinois, $161 million, it said.
- “This report confirms that the Department of Energy’s unlawful mandates amount to a self-inflicted rate hike in nearly every region of the country,” Ted Kelly, director and lead counsel for U.S. Clean Energy at EDF, said in a press release. “These dirty and expensive fossil plants were slated to close for good reason: they cannot compete with cleaner sources of energy that are more affordable and better for our health.”
These problems with aged and inefficient coal plants helps me appreciate China building all of those new coal plants while they were shutting down others.