The Coal Trader

Tri-State moves up closure of coal plant

Tri-State Generation and Transmission Association plans to shutter the last coal-fired power generating unit in Craig two years earlier than previously planned. The move accelerates the end to one of the largest greenhouse gas polluters in Colorado and immediately won praise from environmental groups. 

Tri-State, which sells electricity to local co-ops in Colorado and other Western states, also won praise Friday for becoming first in line for up to $970 million in new clean energy grants and low-cost loans from a U.S. Department of Agriculture program for rural America. Tri-State’s new long-term energy plan now calls for 1,250 megawatts of renewable generating sources and utility-scale battery storage to smooth out supplies from solar and wind generation. 

Tri-State in recent years has suffered defections by co-ops who wanted to offer customers clean renewable sources of electricity sooner, and sought more control over their supply. Those member departures made an earlier closing of Craig 3 economically necessary, the company said in a description of its 2023 Electric Resource Plan that still must be approved by the Colorado Public Utilities Commission.

“Our rapid transition increases clean energy used by our members to 50% in 2025 and 70% by 2030, benefiting members with lower and stable priced renewable energy resources,” Tri-State CEO Duane Highley said. “Through 2043, our plan reduces costs to our members by more than $1.8 billion compared to business as usual.” 

The emissions reductions are significant, the Sierra Club said in a statement. “But it’s also a lot more cost effective for ratepayers at a time when everything is getting more expensive.”

Stacy Tellinghuisen, deputy director of policy development at Western Resource Advocates, a clean energy and environmental nonprofit for Western states, said “Tri-State should be commended for proposing a transformational electric resource plan, which will reduce carbon pollution across the West and provide economic benefits for its member cooperatives. We encourage other utilities to take advantage of this once-in-a-generation opportunity to use federal funds to replace expensive, polluting plants with cleaner resources.”

Craig’s Unit 3, solely owned by Tri-State, will now close by Jan. 1, 2028, instead of Dec. 31, 2029 as previously announced. Unit 2, jointly owned by Tri-State, Xcel, PacifiCorp, Platte River Power Authority and Salt River Project, will close on Sept. 30, 2028. Unit 1, with the same joint ownership, will close by the end of 2025, spokesman Mark Stutz said. 

Also Friday, Tri-State said for the first time it has an ending date for a unit it owns at Springerville power plant in eastern Arizona, near the New Mexico border. Tri-State owns all of Unit 3, at 458 megawatts, and will close it in 2031 as part of its Electric Resource Plan filed with the PUC. That unit was built in 2006 with a 60-year projected lifespan, according to WRA, which said it worked with Tri-State throughout 2023 on developing the clean energy alternatives. 

Two other units of Springerville, owned by Tucson Electric Power, will be retired in 2027 and 2032, WRA said. A fourth unit owned by Salt River Project still does not have a closing date, WRA said. 

The new federal funding will help Tri-State pursue an overhaul of its electric power by 2031, company officials said. Tri-State is pursuing a maximum $970 million share of the $9.7 billion Empowering Rural America fund, one of the many clean energy subsidies included in the Inflation Reduction Act.

They plan to build 500MW of wind, 200MW of wind with storage capacity, 310MW of storage that will include iron air battery arrays supplying 100 hours of backup power, separate 4-hour battery arrays, and 240MW of solar. Xcel has also announced an iron air battery facility to be located near its Comanche coal fired station in Pueblo, scheduled for final closure by 2031 as the last standing coal-fired plant in the state. 

Tri-State also wants to build a new “dispatchable” natural gas-fired power plant to help fill in any gaps left by intermittent renewable energy. 

If the federal funding comes through and the plan is fully carried out, Tri-State said the changes will cut the association’s greenhouse gases by 89% from the 2005 baseline used in state planning. 

All the units of Craig station together produced just under 8 million tons of carbon dioxide greenhouse gas pollution in 2022, according to the EPA, the largest single location for emissions in Colorado. Craig Unit 3 produced 2.8 million tons of that carbon total, Sierra Club said, and 1,700 tons of sulfur dioxide that contributes to acid rain. The unit also produced 2,900 tons of nitrogen oxide, which contributes to toxic ground-level ozone, Sierra Club said. 

Springerville Unit 3 emitted more than 2.8 million tons of carbon in 2022. 

Tri-State’s cooperative includes 45 members with more than a million electric customers in four states. 

Here are the Colorado coal-fired plants recently closed or scheduled to close by 2031: 

  • Comanche 1: Closed 2022, Pueblo, 325 MW, owned by Xcel
  • Martin Drake: Closed 2022, Colorado Springs, 207 MW, owned by Colorado Springs Utilities
  • Pawnee Station: To close 2025, Fort Morgan, 505 MW, owned by Xcel. (Closure of the coal-fired portion, with some of the plant retrofitted to burn natural gas.)
  • Craig Unit 1: To close 2025, Craig, 427 MW, operated by Tri-State and co-owned by PacifiCorp, Platte River Power Authority, Salt River Project, Tri-State Generation and Transmission Association and Xcel
  • Comanche 2: To close 2025, Pueblo, 335 MW, owned by Xcel
  • Hayden Unit 2: To close 2027, Hayden, 135 MW, owned by Xcel, Salt River Electric Cooperative, and PacifiCorp
  • Hayden Unit 1: To close 2028, Hayden, 98 MW, owned by Xcel, Salt River Electric Cooperative, and PacifiCorp
  • Craig Unit 2: To close 2028, Craig, 410 MW,  co-owned by PacifiCorp, Platte River Power Authority, Salt River Project, Tri-State Generation and Transmission Association and Xcel
  • Craig Unit 3: To close now by Jan. 1, 2028, Craig, 448 MW, owned by Tri-State 
  • Rawhide: To close 2030, Wellington, 293 MW, owned by Platte River Power Authority
  • Comanche 3: To close by 2031, Pueblo, 750 MW, owned by Xcel