The North American Electric Reliability Corporation’s (NERC) 2026 State of Reliability report contains lessons for Colorado’s electricity sector. While the grid as a whole “continues to deliver reliable electric service,” challenges are mounting thanks in part to the “declining availability of aging combustion generation.”
NERC’s report finds that power plants failed more in 2025, with the fleet-wide forced outage rate climbing to 9.2 percent against “historical norms rarely exceeding” 8 percent. Coal-fired plants saw their forced outage rate rise from 11.2% in 2024 to 14.1% in 2025.
NERC surveyed owners of generators that saw substantial increases in outages from 2024 to 2025 and found that of the 26 responses from generators, 16 units “experienced equipment destruction extensive enough to significantly prolong their 2025 outage(s),” another eight experienced supply chain constraints, and six indicated turbine blade release or vibration that needed addressing. NERC also points out that regulatory reasons for outages were the “most consistently increasing” cause of outages between 2017 and 2025, though those “did not indicate any alignment with a particular policy objective.”
If this sounds like Xcel Energy’s Comanche 3, you’d be right. The 750 MW unit near Pueblo, Colorado’s largest coal unit, has been offline since August 2025 for turbine repairs and is expected to be back only by July 2026. Coal’s share of Colorado generation fell from 28.1 to 23.7 percent in 2025, almost entirely because of that one outage.
NERC explains that the results of its survey of coal plant outages “align with, but do not prove, industry assertions concerning coal and combined-cycle units.” NERC goes on to say that these units “were not designed for regular cycling,” which is now an “operational requirement” given regulation and the intermittent resources that are trying to replace baseload coal and natural gas. NERC points out that inverter-based resources (meaning wind, solar, and batteries) are increasing operational complexity, especially in areas with “high renewable penetration during light-load conditions.”
Comanche 3 averaged 91.5 outage days per year, traced to construction defects and poor maintenance. But Xcel has no incentive to rigorously maintain its coal-fired generation, either, given that Colorado’s 2019 climate law requires Xcel to cut emissions 80 percent by 2030 and forces premature retirements. Asked why the state’s coal plants struggled in August, the Public Utilities Commission’s Erin O’Neill said that “we have been trying to make sure we don’t overinvest on maintenance on units that are… reaching their retirement date.”
There is no near-term substitute for Comanche 3, and Xcel told regulators it has no viable alternatives to repairing Comanche 3, that replacing its capacity would cost billions and could not arrive before 2029. The PUC extended 50-year-old Comanche 2 through the end of 2026 to cover the shortfall, and the Department of Energy ordered Craig Unit 1 to stay open past its planned 2025 retirement. Even running Comanche 3 at its $66.25 per megawatt-hour over its first decade will be cheaper, faster, and more reliable than spending billions to build new wind and solar.
Colorado is a leading example of what NERC found across the country. Its 2019 emissions mandate sets early retirement dates for baseload coal and natural gas plants and requires intermittent replacements, encouraging Xcel Energy to allow plants like Comanche 3 to fall into disrepair. Why maintain it properly when the state is going to force the company to abandon that asset anyway?
