1952 – Tri-State was formed by 26 rural electric cooperatives and public power districts as a central source of wholesale power. The member systems served a combined total of 41,000 end-use consumers.
1957 – The association opened its first office in Loveland, Colo.
1966 – Tri-State dedicated its Sidney, Neb., facilities, which included the Sidney substation and a 230-kilovolt transmission line.
1975 – Tri-State’s first power plant, the Republican River Station in Wray, Colo., was brought on-line in June to meet soaring summer peak demand.
1976 – The nation’s first DC Tie was completed by Tri-State in Stegall, Neb., and began operation the following March. This facility allows power to flow between the two electrical grid systems of the eastern and western United States.
1977 – Tri-State began dispatching its own power from its headquarters in Thornton, Colo.
1979 to 1980 – The Yampa Project, encompassing Craig Station’s Units 1 and 2, began commercial operation in Craig, Colo.
1982 – The last of three units at Laramie River Station near Wheatland, Wyo., began commercial operation.
1984 – The association dedicated its operations center in Westminster, Colo. Tri-State also signed its first long-term surplus energy sales contracts with Public Service Company of Colorado (now Xcel Energy) for energy sales continuing into 2001.
1986 – The G&T’s energy management system was completed with its members serving 141,137 consumer meters.
1989 – Tri-State reached an equitable, precedent-setting agreement of a four-year dispute over the right of a Tri-State member to sell its assets to another utility and discontinue purchasing power from the association.
1992 – The bankruptcy reorganization and acquisition of major portions of the assets of Colorado-Ute Electric Association of Montrose, Colo., was completed. Tri-State acquired the lease of Craig Station Unit 3 and ownership of the 100-megawatt Nucla Station in southwestern Colorado. Approximately 675 former Colorado-Ute employees and 10 new member systems joined the association.
1997 – The five-year consolidation of Tri-State and Colorado-Ute culminated in the spring when personnel moved into a new headquarters building in Westminster, Colo.
1998 – Tri-State became a founding member of the Touchstone Energy brand identity program, which would grow to include hundreds of participating electric co-ops across the United States.
2000 – Tri-State completed a merger with Plains Electric Generation and Transmission Cooperative of Albuquerque, N.M., thereby adding 12 New Mexico cooperatives to its member distribution system network. With the merger, Tri-State became owner and operator of the 250-megawatt Escalante Generating Station located near Prewitt, N.M., and with the added personnel, the G&T's workforce increased to more than 800 employees.
2001 – Cementing the long-term obligation between Tri-State and its members, all 44 member systems signed new, all-requirements contracts that extended their continued exclusive electricity service from Tri-State through the year 2040.
2002 – Tri-State’s biggest environmental upgrade in its history began in spring 2002 at Craig Station. It marked the beginning of a three-year project, prompted by a settlement agreement reached between the Sierra Club and the five utilities comprising the Yampa Project (including Tri-State), which share ownership in the plant.
2002 – Construction of the two-unit Limon Generating Station south of Limon, Colo., and the similarly designed Knutson Generating Station near Brighton, Colo., was completed and both stations became commercially available in spring 2002.
2002 – Four years after Tri-State first began buying power from an 85-megawatt, gas-fired, combined-cycle power plant located near Rifle, Colo., the G&T completed a transaction to purchase this facility on Sept. 25, 2002. Formerly called American Atlas No. 1, the plant is now known as Rifle Generating Station.
2002 – Tri-State celebrated its 50th anniversary during the association’s annual meeting in April 2002.
2003 – After leading the company for 14 years, Tri-State’s executive vice president and general manager Frank Knutson retired. He was replaced by 35-year electric utility industry veteran J.M. Shafer.
2003 – Construction and commissioning of Pyramid Generating Station, located near Lordsburg, N.M., was completed on schedule in April. The facility is used during high-peak periods and as back-up generation to support Tri-State’s southern system.
2006 – Construction was completed at Tri-State's 418-megawatt Unit 3 at Springerville Generating Station in eastern Arizona. The $939 million project marked the first new baseload resource added to the G&T's system in more than 20 years.
2007– In response to growing interest in green power options by Tri-State’s member systems and renewable portfolio standards adopted in
Colorado and New Mexico, the G&T took several steps to secure more renewable resources. A request for proposals was issued for renewable resources to be available in 2009; in addition Tri-State began to participate in
research activities in several renewable projects.
2008 – Ken Anderson was named executive vice president and general manager – succeeding J.M. Shafer – becoming Tri-State’s seventh general manager since its inception in 1952.
2008 – The Colorado Department of Public Health and Environment awarded Tri-State’s 100-megawatt Nucla (Colo.) Station as a Bronze Achiever under the Colorado Environmental Leadership program for making significant achievements in operating the power plant in compliance with all air, land and water regulations – making Tri-State the only electric utility in the state to be admitted into the program.
2009 – Tri-State and First Solar (Tempe, Ariz.) signed an agreement to develop one of the largest solar photovoltaic facilities in the world – the “Cimarron Solar Project.” The 30-megawatt power plant will be built on a 250-acre site in Colfax County in northeastern New Mexico, within the service territory of Tri-State member system Springer Electric Cooperative. Construction of the facility commenced on April 2010 and was operational by the end of that year.
2009 – Tri-State and Duke Energy (Charlotte, N.C.) signed an agreement to develop a 51-megawatt wind farm in eastern Colorado’s Kit Carson County, within the service territory of Tri-State member system K.C. Electric Association. Tri-State will purchase the power generated at “Kit Carson Windpower Project” over a 20-year period. Construction of the facility, which consists of 34 1.5-megawatt General Electric turbines, commence on June 2010 and was operational by the end of that year.
As the owner/operator of the 245-megawatt Escalante Generating Station in Prewitt, N.M., Tri-State became only the eighth company in the state to earn the prestigious Zia Star Voluntary Protection Program status from the New Mexico Environment Department’s Occupational Health and Safety Bureau in conjunction with the federal Occupational Safety and Health Administration.
2011 – Tri-State purchased Fort Lupton Generating Station and completed the acquisition of Colowyo Mine by Tri-State subsidiary Western Fuels-Colorado, along with a flurry of field projects aimed at making improvements to the association’s power delivery system.
2012 – Tri-State’s renewable energy portfolio expands with the completion and addition of the 67-megawatt Colorado Highlands Wind project in northeast Colorado. Tri-State signed a 20-year power purchase agreement to buy all of the electric output from the project’s joint owners, Alliance Power, Inc. of Centennial, Colo., and GE Energy Financial Services of Stamford, Conn. The 42-turbine wind farm is located on a 5,200-acre site in Logan County, within the service territory of Tri-State member co-op Highline Electric Association.
Updated: February 11, 2013