Sherburne County (Sherco) Generating Station

Location: Becker, Minn., 45 miles northwest of the Twin Cities, on the Mississippi River.

Plant Description: Sheer size sets the Sherburne County Generating Plant (Sherco) apart from the company’s other generating facilities. Sherco is the largest in terms of square feet, steam production, power generation capability and coal consumption.

Power Production Capability: 2,400 megawatts (MW) , Unit 1 – 750 MW ; Unit 2 – 750 MW; Unit 3 – 900 MW

Fuel Source: Low-sulfur Western coal from mines in Montana and Wyoming. The plant burns 30,000 tons of coal every day (three trainloads) and more than nine million tons a year. A rotary car dumper, which literally turns a rail coal car upside down, unloads one car every three minutes and an entire train in just over six hours.

Sherco’s boilers are more than 200 feet tall — taller than the dome of the Minnesota State Capitol building — and together can burn more than 1,300 tons of coal an hour. Each boiler weighs about 8 million pounds and contains about 200 miles of steel tubing. In addition to supplying steam to turn the plant’s turbine-generators, the boilers provide process steam for a neighboring paper manufacturing facility

The Unit 3 generation building is more than fifteen stories high and the stack, or chimney, extends 650 feet — as tall as several downtown Minneapolis office towers. The plant’s coal barn — longer than a football field — provides dry storage for coal, cutting down on dust and improving coal handling efficiency.

Sherco has generated more than 377 million megawatt-hours of electricity its 30-year history. That’s enough electricity to power a single average home for forty-five million years and the entire community of Becker for some 34,000 years.

If Sherco were converted to a high efficiency natural gas powered plant, the natural gas consumption would be 80 percent of that used by all Minnesota customers combined.

The plant’s typical availability factor of 95 percent is well above the national average of 78 percent for coal plant availability.

Sherco Units 1 and 2 were built in the 1970s to meet the growing demand for electricity and to reduce the use of older, less efficient plants. The plant was constructed on a 4,500-acre site to accommodate future expansion. A third unit was built in 1983-1987, which at the time marked the largest construction project ever in the state of Minnesota. Unit 3 cost approximately $1 billion to build and involved more than 1,000 craft workers in construction. Unit 3 went into operation two months ahead of schedule and $68 million under the original estimate. The unit is 41 percent owned by Southern Minnesota Municipal Power Agency, composed of municipal power companies operating on a cooperative basis.

Sherco reflects the company’s environmental commitment, with its modern and efficient air quality control systems. Unit 3’s dry scrubber system, which uses a mist of lime slurry in spray dryers to trap sulfur dioxide, is the world’s largest air quality system for a single unit. Units 1 and 2 have wet scrubbers, which use an alkaline spray to capture sulfur dioxide and ash. The plant also installed new wet electrostatic precipitator (ESP) technology on its two older units to reduce particulate emissions. Sherco employs continuous emissions monitors to ensure it operates within state and federal air quality permit limits.

 Sherco employees deliver Meals on Wheels and volunteer to serve in a Becker community senior congregate dining program. Plant employees also are active participants in local United Way efforts. Through its plant advisory committee, Sherco leadership has forged a partnership with other community leaders on local issues and economic development efforts.

Sherco employs more than 350 people full time and hires contract crews for special projects. Property taxes from the plant benefits the city, county and school system.