Tri-State Generation and Transmission Association, Inc.

Craig Station is a key baseload resource providing the association with a total of 655 megawatts of relatively low-cost, reliable generation . Operated by Tri-State, approximately 300 people work at the 1,311-megawatt plant. Craig Station Units 1 and 2 make up the Yampa Project, owned by Tri-State and four other regional utilities. Tri-State is the sole owner of Unit 3.

In 2002, the association embarked on its largest environmental project upgrade in its 50-year history at Craig Station. It marked the beginning of a $121 million, multi-year retrofit to Units 1 and 2 to address opacity concerns and the mitigation of particulate matter. The upgrades were prompted by a settlement agreement reached between the Sierra Club and the five owner utilities of the Yampa Project.

Plant Statistics

Plant operator	Tri-State G&T
Plant construction	1974 to 1984; construction was completed on Unit 2 in 1979, Unit 1 in 1980 and Unit 3 in 1984
Total project cost	$1.2 billion
Total capacity	1,311 megawatts (net); Tri-State share - 655 megawatts (24 percent of Units 1 and 2; 100 percent of Unit 3)
Coal source	Trapper, Colowyo and other mines in the region
Plant site size	1,120 acres
Stack height	600 feet (each)
Water source	Yampa River; supplemental allocations from Elkhead Creek Reservoir (Units 1 and 2) and Yamcolo Reservoir (Unit 3)
Environmental controls	A wet limestone scrubber system removes 90 percent of the sulfur dioxide produced for Units 1 and 2, while a dry lime system is used for Unit 3; fabric-filter baghouse collects 99 percent of fly ash; state-of-the-art low-NOx burners and over-fired air reduce the formation of nitrogen dioxide; a continuous 24-hour emissions-monitoring system ensures that flue gas emissions comply with federal and state laws

Coal Supply

Craig Station receives its coal supply primarily from two sources: Trapper Mine, located one mile south of the plant and Colowyo Mine sited about 30 miles southwest of the station.

Trapper Mine, which is owned by Tri-State and certain members of the Yampa Project, delivers coal to the plant via 100-ton haul trucks from the mine site. Colowyo Mine delivers coal to Craig Station daily by train.

The station also augments these two sources of coal with spot coal purchases from other mines in northwestern Colorado.

Trapper Mine Statistics

Ownership	Trapper Mining, Inc.
Mine site size	10,000 acres
Annual yield	2.3 million tons
Daily production	7,000 to 10,000 tons

Colowyo Mine Statistics

Ownership	Western-Fuels Colorado
Mine site size	12,000 acres
Annual yield	2.3 million tons
Daily production	10,000 tons

Nucla Station near Nucla, Colo., produces 100 megawatts of generating capacity and is the world's first utility-scale power plant to utilize atmospheric circulating fluidized-bed combustion. The station employs more than 50 people in southwestern Colorado.

Plant Statistics

Plant owner and operator	Tri-State G&T
Plant construction	1957 - 1959
Re-powering project	1985 - 1987
Total project cost	$112 million
Total capacity	100 megawatts (net)
Coal source	New Horizon Mine
Plant site size	60 acres
Stack height	215 feet
Water source	San Miguel River; supplemental allocations from Trout Lake
Environmental controls	Atmospheric circulating fluidized-bed combustion that provides more than 70-percent capture of sulfur dioxide emissions and reduces the formation of nitrogen dioxide; fabric-filter baghouse that collects 90 percent of all particulates

Coal Supply

Nucla Station receives its coal supply exclusively from New Horizon Mine, five miles south of the plant, by tractor-trailer truck. The station takes delivery of up to 64 25-ton loads each day.

Environmental Leadership Award

The Colorado Department of Public Health and Environment (CDPHE) has awarded Tri-State as a Bronze Achiever under the Colorado Environmental Leadership program (ELP) for making significant achievements in operating its 100-megawatt Nucla Station in compliance with all air, land and water regulations. Tri-State is the only electric utility in the state to be admitted into the program, which has been in place since 1999.

Located outside the southwestern Colorado town for which it is named, the power plant was selected for the ELP award due to its implementation of the Environmental Management System (EMS) over the past eight years. “This is a great achievement for our employees at Nucla Station,” said Mike McInnes, Tri-State’s senior vice president of production. “It serves as an acknowledgment of the measures that we are already taking at our power plants to meet environmental compliance requirements.”

New Horizon Mine Statistics

Ownership	Western Fuels-Colorado
Mine site size	20 acres
Annual yield	350,000 to 400,000 tons
Daily production	1,600 tons

Escalante Station Escalante Generating Station near Prewitt, N.M., is a single-unit, 250-megawatt, coal-fired power plant. With a work force of about 120 employees, the station produces a majority of the electricity used by more than 250,000 end-use consumers comprising the 12 Tri-State member utilities operating in New Mexico. In addition to providing electric power, Escalante supplies excess steam to the adjacent McKinley Paper Co. for the manufacture of linerboard.

Plant Statistics

Plant owner and operator	Tri-State G&T
Plant construction	1980-1984
Total project cost	$450 million
Total capacity	245 megawatts
Coal source	Lee Ranch Mine
Plant site size	2,560 acres
Stack height	450 feet
Water source	underground wells
Environmental controls	A wet limestone scrubber system removes 90 percent of the sulfur dioxide produced at the plant; fabric-filter baghouse collects 99 percent of fly ash; continuous 24-hour emissions monitoring system assures that flue-gas emissions comply with federal and state laws

Coal Supply

Escalante Generating Station receives its coal supply primarily from Lee Ranch Mine, 35 miles north of the plant, by rail. Sixteen trains per month with 52 100-ton railcars deliver the coal.

Lee Ranch Mine Statistics

Ownership	Peabody Natural Resources
Mine site size	16,000 acres
Annual yield	5.5 million tons
Daily production	16,000 tons

Laramie River Station located near Wheatland, Wyo., is a three-unit, 1,710-megawatt, coal-fired electric generating facility. Part of the Missouri Basin Power Project, LRS is owned by six participants including Tri-State, which owns a 24 percent capacity share of the plant.

Plant Statistics

Plant operator	Basin Electric Power Cooperative, Bismarck, N.D.
Plant construction	1976-1982
Total project cost	$1.6 billion
Total capacity	1,710 megawatts Tri-State share - 410 megawatts
Coal source	Coal is shipped by rail to the plant from mines in the Powder River Basin.
Plant site size	650 acres
Stack height	604 feet (each)
Water source	Grayrocks Dam and Reservoir
Environmental controls	Electrostatic precipitators remove 99 percent of fly ash and scrubbers remove 80 to 90 percent of sulfur dioxide from stack emissions; low-NOx burners reduce the formation of nitrogen dioxide

Coal Supply

Laramie River Station receives its coal supply from various mines, including Dry Fork Mine, in the Powder River Basin, located about 190 miles north of the plant. More than 40 trains per month, each averaging 136 120-ton railcars deliver the coal to the station's coal yard.

Dry Fork Mine Statistics

Ownership	Western Fuels-Wyoming
Mine site size	7,000 acres; 4,160 acres of federal and Wyoming coal leases
Annual yield	5.6 million tons
Daily production	13,000 tons

San Juan Generating Station located near Farmington, N.M., is four-unit coal-fired facility that provides Tri-State with about 41 megawatts of capacity. In January 1996, Tri-State purchased an 8.2 percent share from Unit 3 at the plant, which is operated by Albuquerque, N.M.-based Public Service New Mexico. San Juan Generating Station is the seventh-largest coal-fired station in the West.

Plant Statistics

Plant operator	PNM
Plant construction	1973
Total capacity	1,800 megawatts (gross) Tri-State share – 40 megawatts (8.2 percent of Unit 3)
Coal source	San Juan Coal Company – BHP Billiton
Plant site size	521 acres
Stack height	400 feet (each)
Water source	San Juan River
Environmental controls	A state-of-the-art limestone forced-oxidation system removes 80 percent of all sulfur dioxide produced at the plant; electrostatic precipitators remove 99 percent of fly ash and low-NOx burners reduce the formation of nitrogen dioxide; continuous 24-hour emissions monitoring system ensures that flue gas emissions comply with federal and state laws

Coal Supply

San Juan Generating Station receives its coal supply primarily from San Juan (underground) Mine, about two miles from the plant by truck.

San Juan Mine Statistics

Ownership	San Juan Coal Company - BHP Billiton
Mine site size	17 square miles
Annual yield	7.8 million tons
Daily production	17,810 to 19,810 tons per day (average)

Springerville Generating Station located in east-central Arizona, is a three unit coal-based, 1,178-megawatt power plant operated by Tucson Electric Power. In 2006, a third unit producing 418 megawatts was added by Tri-State. Under contractual agreements, Tri-State, as the lease holder of Unit 3, is taking 418 megawatts of capacity from the unit and selling a portion of its output to other regional utilities.

Plant Statistics

Plant operator	Tucson Electric Power
Plant construction	2003-2006
Total project cost	$935.7 million
Total capacity	418 megawatts
Coal source	North Antelope Rochelle Mine, Wyo. (Unit 3); Lee Ranch Mine, N.M. (Units 1 and 2)
Plant site size	22 acres
Water source	Well Water
Environmental controls	State-of-the-art equipment was designed for the flue gas cleanup system, such as low NOx burners and selective catalytic reduction (SCR) for NOx control, dry flue gas desulfurization (DFGD) system for SO2 control and the pulse jet baghouse for particulate control, for a continuous 24-hour emissions monitoring to assure compliance with the federal and state regulations.

Coal Supply

Springerville Generating Station’s Unit 3 receives its coal supply by rail primarily from North Antelope Rochelle Mine, nearly 65 miles south of Gillette, Wyo., in the Powder River Basin. Ten trains per month with 128, 120-ton railcars deliver the coal.

North Antelope Rochelle Mine Statistics

Ownership	Powder River Coal Company (Peabody)
Mine site size	Approximately 11,000 acres
Annual yield	80 million tons
Daily production	220,000 tons