December 1, 2023: Following years of Sierra Club’s multi-pronged advocacy for Tri-State Generation & Transmission Association to transition from fossil fuels to clean energy, Tri-State filed a plan with the Colorado Public Utilities Commission to retire and replace two large coal units by 2031. Under Tri-State’s plan, Craig Unit 3, a 448 MW coal unit in Colorado, would retire on January 1, 2028; and Springerville Unit 3, a 420 MW coal unit in Arizona, would retire by September 15, 2031. The proposed retirement of Springerville Unit 3 is particularly significant because it was one of the last coal units built in the West, coming online in 2006. Tri-State has proposed to replace these units primarily with renewables and battery storage, funded in part through federal money available through a provision in the Inflation Reduction Act intended to help rural electric utilities reduce greenhouse gas emissions (the program is called “New ERA”). Tri-State provides wholesale electricity to rural electric cooperatives who serve over 1 million customers in Colorado, Nebraska, New Mexico, and Wyoming.
Retiring these two coal units would reduce CO2 emissions by over 5.5 million tons, reduce SO2 emissions by nearly 3,000 tons, and reduce NOx emissions by nearly 4,000 tons per year. This will significantly improve public health by reducing premature deaths, heart attacks, respiratory diseases, and asthma attacks caused by these coal units’ emissions. In addition, Tri-State estimates that its proposal would save customers hundreds of millions of dollars.
Tri-State’s announcement is the product of years of legal, grassroots, and legislative advocacy. On the legal front, Sierra Club won rulings from the Colorado PUC requiring Tri-State to analyze early retirement of Craig 3 and Springerville 3. Environmental Law Program attorney Matthew Gerhart has represented Sierra Club in Tri-State’s resource plan proceedings at the Colorado PUC, including the current case. Sarah Snead, Anna McDevitt, Grace Thorvilson, and consultant Joan May organized an effective campaign, assembling a broad grassroots coalition to press Tri-State to transition to clean energy. At the federal level, Jeremy Fisher, Jonathan Levenshus, Patrick Drupp, and Neil Waggoner introduced and helped secure passage of the Inflation Reduction Act provisions that became the New ERA program (from which Tri-State has requested federal funding to retire and replace Craig 3 and Springerville 3).