One turbine at a massive Colorado coal plant will live to see 2026. Another might not be so lucky.
Their fate at the Comanche Generating Station has massive implications for Colorado’s climate goals. Closing the behemoth facility outside Pueblo is key to the state’s plan to cut planet-warming pollution 50 percent of 2005 levels by 2030. Comanche is one of Colorado’s largest carbon dioxide polluters.
State regulators envisioned a gradual phaseout of the plant’s three turbines, the first of which closed in 2022. A second 1970s-era turbine was set to close later this year. But that plan went out the window when the plant’s newest and largest turbine was forced offline in August after experiencing “elevated vibrations.”
Last week, regulators on the Colorado Public Utility Commission approved a request by Comanche’s owner and state officials to keep the older unit running for an additional year while the faulty turbine is fixed. Yet even as they approved the request, regulators indicated that the broken unit might not be worth the money to repair.
The 856-megawatt turbine known as Comanche 3 has suffered repeated mechanical problems since it came online in 2010. The unit has been down for repairs almost three years of its lifespan, altogether.
Commissioners excoriated Xcel, the unit’s largest owner, by saying the utility had failed to outline how much it would cost to repair Comanche 3. Xcel has said it expects the unit will come online by summer.
“We are in the dark about what any of this costs. We are just in a real reliability pickle because once again Unit Three has broken in a catastrophic way,” said Commissioner Megan Gilman.
PUC Chair Eric Blank said he wanted more “visibility into what’s going on ahead of time.”
Another commissioner, Tom Plant, called it “bizarre” that Xcel had apparently identified the problem and how long it would take to fix it without providing a cost estimate.
“How do you go into a project like this, a multimillion-dollar project, without even a ballpark estimate of what your costs are going to be, with the assumption that it’s just going to be approved and passed on to ratepayers,” he said. “I just find that mind boggling.”
Those are stern warnings in the mundane world of utility regulation. As a regulated monopoly, Xcel can pass along the costs of its repairs to customers — if regulators provide their approval. The prospect of the PUC rejecting requests to repair Comanche 3 could lead to a prolonged closure of the unit, and the possibility that Xcel and its investors would have to bear the cost of fixing it.
Both options have the potential to be politically explosive. The debate over Comanche’s future comes as electricity demand is rising, igniting speculation that the Trump administration could issue an emergency order directing Comanche’s older 396-MW turbine to stay open.
“It sends a pretty strong message to investors that it’s going to be risky for the investors if they continue to rely on plants that have big reliability issues like Comanche 3,” said Michelle Solomon, an analyst who tracks the electricity industry at the clean energy think tank Energy Innovation.
This isn’t the first time regulators have balked at the idea of consumers paying for cost of fixing Comanche 3, said Jeffrey Ackermann, a former PUC chair. In 2019, the commission voted to disallow $11.9 million in repairs to the unit. It later walked back that decision on appeal, but distrust of Comanche 3’s mechanical resilience continues to linger, he said. The plant spent most of 2020 out of operation.
“I think we let the utility get way too much,” said Ackermann, noting that Comanche 3 has not performed to the level promised by Xcel. “You’re not honoring your side of the bargain. Why do we have to honor ours? And I think that that point really needs to be brought home even more sternly, making utilities have to really operate like true businesses that have to understand risk and anticipate uncertainty and then incur ups and downs of that.”
Comanche was Colorado’s largest coal plant — and its biggest carbon dioxide polluter. Between 2011 and 2019, Comanche released almost 84 million tons of climate pollution annually, according to EPA data. Its average yearly emissions of 9.3 million tons during that time was roughly equivalent to the output of 2 million cars. Comanche 3 accounted for about half of those emissions, with an annual average of almost 4.7 million tons.
Shuttering the plant was supposed to be an orderly affair, with turbines gradually be phased out as newer, cleaner ones came online. Comanche 1, a 365-MW turbine, closed in 2022. Comanche 2 was supposed to follow this year, and Comanche 3 was supposed to run through 2031.
Xcel told the PUC in a joint filing last month with the Colorado Energy Office and the Utility Consumer Advocate that the move to keep Comanche 2 open would ensure reliability and insulate consumers from wintertime price spikes.
“We appreciate the approval to extend Comanche 2 through December 31, 2026, as it provides an essential reliability resource that will be needed throughout 2026, even after Comanche 3 returns to service in the middle of next year,” the company said in a statement.
Xcel said it remains committed to Colorado’s clean energy goals but declined further comment until the commission releases a written version of its order.
Whether state officials share the PUC’s concerns over Comanche 3 isn’t clear. Josh Chetwynd, a spokesperson for the Colorado Energy Office, did not respond to a question about the commissioners’ stern warnings related to the unit’s frequent breakdowns.
“Colorado is well on its way to achieving 100 percent clean energy and reducing emissions while saving people money and ensuring energy reliability,” he said.
