Reliable, lowest-cost, reduced emissions preferred portfolio focus of Tri-State resource plan filing 

• Preferred portfolio bolsters reliability, meets state environmental and renewable energy requirements at the least cost among six portfolios.
• Hydrogen-blend capable natural gas facilities ensure reliability.
• Moffat County, City of Craig leaders laud new investments in northwest Colorado.

(April 11, 2025, Westminster, Colo.) Delivering on its commitment to a reliable, affordable and responsible electric system to serve its rural members well into the future, not-for-profit wholesale power supply cooperative Tri-State Generation and Transmission Association filed its 2023 Electric Resource Plan (ERP) Phase II Implementation Report today with the Colorado Public Utilities Commission (CoPUC). 

The report identifies Tri-State’s preferred portfolio, which is the least-cost mix of diverse generating resources, compared to other evaluated portfolios. The preferred plan meets Tri-State’s enhanced reliability metrics, and stringent state greenhouse gas emissions reduction and renewable energy requirements.

“Tri-State’s preferred portfolio presents a resource plan that meets both industry-standard and heightened extreme weather reliability metrics, while also meeting state requirements for greenhouse gas emissions reductions and renewable portfolio standards. It does so at a lower cost than the alternative portfolios,” said Tri-State Chief Executive Officer Duane Highley. “This portfolio outlines the most cost-effective path for Tri-State to meet our mission to serve our members a reliable, affordable and responsible supply of electricity designed for the future.”

Following an uncontested, comprehensive settlement of the first phase of the ERP process, in September 2024 Tri-State issued three requests for proposals for new renewable, storage and dispatchable resources, and then modeled six unique portfolios to evaluate bid selection.

All of the portfolios modeled meet industry-standard Level 1 and Tri-State’s heightened Level 2 reliability metrics, which demonstrate resource adequacy in extreme winter and summer weather events; achieve at least an 80% reduction in greenhouse gas emissions associated with Tri-State’s Colorado wholesale electric sales by 2030, relative to a 2005 baseline; and meet both Colorado and New Mexico’s Renewable Energy/Portfolio Standards. Tri-State forecasts that 70% of the energy it provides to its members will come from renewable resources in 2030.

Tri-State details preferred portfolio

Tri-State’s preferred portfolio is the least-cost portfolio and selects 10 new resource bids with commercial operations dates between 2026 and 2031, totaling 1,657 megawatts (MW) across Tri-State’s four planning regions, including:

• 700 MW of renewable power purchase resources:
  • 200 MW solar in Eastern Colorado (2028)
  • 100 MW solar/battery hybrid in New Mexico (2028)
  • 200 MW wind in Eastern Colorado (2029)
  • 200 MW wind in Wyoming/Western Nebraska (2030
• 650 MW of contracted hybrid and standalone short-term storage resources:
  • 50 MW battery in Western Colorado (2026)
  • 150 MW battery in Eastern Colorado (2027)
  • 50 MW battery/solar hybrid in New Mexico (2028)
  • 100 MW battery in New Mexico (2028)
  • 100 MW battery in Eastern Colorado (2028)
  • 200 MW battery in Moffat County, Colo., in Western Colorado (2030)
• 307 MW owned natural gas combustion turbine facility with hydrogen-blend capability in Moffat County in Western Colorado (2029).

Tri-State’s preferred plan reflects previously announced retirements, driven primarily by economics, for Craig Station Unit 1 by the end of 2025; retirement of Craig Station Units 2 and 3 in 2028 in Moffat County; and with agreement with other parties, retirement of Springerville Station Unit 3 in 2031 in Springerville, Arizona. It also includes replacement of five combustion turbines at an existing natural gas plant, J.M. Shafer Station in Fort Lupton, Colo., bringing the station’s nameplate capacity to 281 MW. The turbines are also hydrogen-blend capable.

“Due to the significant increase in renewable energy on the regional grid, these limited natural gas projects are critical for shoring-up capacity during times of high demand, low renewable output, or extreme weather conditions,” Highley said. “The hydrogen-blend capabilities at these gas plants helps future-proof the facilities while ensuring reliability.”

The preferred portfolio is optimized to avoid $370 million in transmission capital expenditures through 2031, through the selection of projects that use surplus transmission interconnections or otherwise do not require significant network upgrades. 

The preferred portfolio is subject to review, modification and approval by the CoPUC, following comments by intervenors.

Strong support for natural gas, storage investment in Northwest Colorado

Supporting Tri-State’s significant investment in renewable resources is a 307 MW natural gas combustion turbine facility with hydrogen-blend capability in Moffat County. The plant will provide operational flexibility to ensure reliability.

Local officials in Craig and Moffat County were an important part of Tri-State’s uncontested settlement for the first phase of the ERP last year, and the preferred portfolio helps to meaningfully address many of the community’s long-term goals in response to the retirement of Craig Station.

Leaders in Moffat County and the City of Craig lauded Tri-State’s preferred portfolio, including investments in the new natural gas combustion turbine power plant and a 200 MW energy storage facility in the county. These resource plan investments are in addition to Tri-State’s 145-MW Axial Basin Solar project, currently under construction in Moffat County, and direct community assistance.

“The City of Craig fully supports Tri-State’s preferred plan, and we are grateful for Tri-State’s continuing commitment to our community,” said Mayor Chris Nichols of Craig. “The retirement of Craig created uncertainty for our future, and while these new investments will not fully replace Craig Station, the fact that Tri-State stepped up to continue as a significant part of our city has done a great deal to help alleviate those concerns.”

“The fact that Tri-State has committed to continuing as a significant entity in Moffat County for decades to come, just has it has been for decades past, is great news and bodes well for the future of our county, from an investment and tax base perspective,” said Moffat County Commissioner Melody Villard. “We look forward to a much brighter, more stable future, one that will include long-term partnership with Tri-State.” 

“These facilities will maintain investment and employment opportunities in Moffat County as the Craig Station retires and ensures Tri-State will continue our long-standing involvement and commitment to the community and northwest Colorado,” Highley said.

“We look forward to continuing to work with state regulators, our members and stakeholders to develop a reliable, affordable and responsible path forward that meets our members’ needs and accomplishes our energy goals,” Highley said.

About Tri-State  

Tri-State is a power supply cooperative, operating on a not-for-profit basis, serving electric distribution cooperatives and public power district member-owners in four states. Together with our members, we deliver reliable, affordable and responsible power to more than a million electricity consumers across nearly 200,000 square miles of the rural West. Visit www.tristate.coop.

Contact:  

Lee Boughey, VP Strategic Communications, 720-670-6696, lee.boughey@tristategt.org  
Mark Stutz, 303-254-3183, mark.stutz@tristategt.org  

 
Certain information contained in this press statement are forward-looking statements including statements concerning Tri-State’s plans, future events, and other information that is not historical information. These forward-looking statements are subject to a number of risks, uncertainties and assumptions, including those described from time to time in Tri-State’s filings with the Securities and Exchange Commission. Tri-State’s expectations and beliefs are expressed in good faith, and Tri-State believes there is a reasonable basis for them. However, Tri-State cannot assure you that management’s expectations and beliefs will be achieved. There are a number of risks, uncertainties and other important factors that could cause actual results to differ materially from the forward-looking statements contained herein.