Tri-State Generation and Transmission Association – Colorado’s second largest electricity provider – has proposed a $21 billion plan to wean itself from a heavy reliance on coal-fired power and move to renewable energy.
The plan would reduce Tri-State’s carbon dioxide emissions by 80% from 2005 levels by 2030 – meeting a state greenhouse gas reduction goal for utilities.
The 20-year resource plan was filed with the Colorado Public Utilities Commission this week, drawing praise for moving toward renewables and criticism from environmental groups for its reduced, but continued, reliance on coal.
For even as Tri-State cuts its carbon emissions 80% in 2030, it still will get 23% of its power from coal-fired plants, according to the plan. About 59% of its electricity will come from renewable sources.
It was the first time Westminster-based Tri-State was required to submit a resource plan to the PUC. “We look forward to engaging with the Colorado Public Utilities Commission and all parties in the regulatory approval process,” Tri-State CEO Duane Highley said in a statement.
Tri-State provides wholesale electricity to 42 rural electric cooperatives in four western states, including 17 in Colorado. Xcel Energy is Colorado’s largest electricity provider.
The plan calls for adding 2,375 megawatts of renewable generation by 2030 and a total of 4,525 MW by 2040. The plan also calls for 200 MW of battery storage and a possible 300 MW of new natural gas capacity’
“It’s encouraging to see Tri-State responding to some of the priorities of its members,” Rebecca Henderson, who gets her power from Tri-State member co-op Poudre Valley Rural Electric Association, said in a statement. Henderson is a co-founder of PVREA Action Group, which since 2018 has pushed the utility for more renewable power. “We’ve been waiting a long time for Tri-State to move more aggressively into clean energy.”
While the power wholesaler will close all of its Colorado coal-fired units by 2030, the plan states that its Laramie River Station coal unit, in Wyoming, would operate until 2033, and its Springerville coal-fired plant in Arizona until 2038.
Tri-State said there is no agreement with the Wyoming plant’s co-owner, the Missouri Basin Power Project, on closing the unit.
“Why Tri-State thinks it makes sense to run the Springerville coal plant — one of its most expensive resources — for another 18 years is beyond me,” said Anna McDevitt, who runs Sierra Club’s Beyond Coal campaign in Colorado and New Mexico.
Henderson called it “troubling” that Tri-State “refuses to let go of coal and gas, which will force us to pay far more for our electricity than customers of other utilities that are transitioning to wind, solar and storage more quickly.”
Tri-State closed its Nucla plant, on the Western Slope, in 2019, and had planned to close all three units of its Craig Station – 1 ,238 MW of coal-fired generation – by 2030. The Colorado Air Quality Control Commission in November ordered the last Craig unit to close by the end of 2028.
Tri-State’s projected 2030 breakdown of electricity supply has 59% coming from renewable generation; 23% from coal; 4% from natural gas; 7% from market purchases and 8% from other nonrenewable sources.
While the initial renewable energy additions will come from long-term contracts with wind and solar developers, energy storage and other technologies may be added later.
“Our preferred scenario identifies potential resource options, including battery storage and natural gas generation, but we do not have to commit to a path at this time,” Highley said. “There will be time for emerging technologies to become competitive before we have to make acquisition decisions.”