Facts and Trivia about Coal Creek Station

Architect - The Coal Creek Station Architect/Engineer was Black & Veatch.

Boiler - Each boiler (steam generator) is capable of burning 490-500 tons of coal per hour. Each produces 3,737,000 pounds of steam per hour to drive the electric generators. The steam is at 2,620 pounds of pressure per square inch, superheated and reheated to 1005 degrees Fahrenheit. The boilers are manufactured by Combustion Engineering.

Boiler Fire-Box - The fire box is 96 feet deep by 43 feet wide by 205 feet high. The boiler is supported from the ceiling and expands 16 inches from cold to hot. Total height of boiler building is 295 feet tall or 29 stories or 456 steps.

Boiler Drum - The boiler drum has a pressure inside that is greater than 2,800 pounds per square inch with water temperature at 675 degrees Fahrenheit.

Boiler Temp - The temperature at the top of the boiler is 2000 degrees Fahrenheit. The boiler tubes can only withstand about 850 degrees Fahrenheit, before they would melt. The water flowing through the tubes keeps them cool.

Bottom Ash - 40% of the bottom ash is marketed for $2.00 per ton.

Chimney Height - The chimney height is 650 feet.

Coal Bunkers - There are eight bunkers per unit, one for each of the eight pulverizers, with a 500 ton capacity. The coal is pulverized into the consistency of face powder. The lignite coal is blown into the boilers where it is burned in suspension.

Coal Burning - Coal Creek Station burns an average of 18,000 to 22,000 tons of lignite coal per day. Coal costs us about $10.08 per ton (that includes all the costs, such as hauling). $74 million was budgeted for 1999.

Coal Reserves - At Coal Creek there is a reserve pile of about 500,000 tons. This would last 22 to 23 days. Falkirk also has a stockpile of 500,000 tons. The coal storage areas are lined with clay.

Condenser - The condenser pumps 150,000 to 200,000 gallons of cooling water every minute through tubes in the condenser to cool and condense the steam exhausted from the turbines. The condensed water (called condensate) is pure distilled water that is pumped with boiler feed pumps back to the boiler.

Control Room - The main control center has been converted to computerized touch screens to operate the plant, and controls over 140 functions. Control lights indicate these processes: Red=Running; Green=Stopped and Save; Yellow=Danger- Ready to run.

Cooling Towers - The three cooling towers, each 42 feet high and 225 feet in diameter, cool the plants circulating water before it goes to the condenser. Each tower is equipped with eight fans with 28-foot diameter blades which draw air across the water as it falls between the slatted walls of the tower. The fans are reversible to prevent freezing in the winter. The water is discharged into a common nine acre extended basin from which circulating water is pumped to the condensers.

Concrete - Total concrete to build the plant was 88,000 cubic yards.

Plant Cost - The cost is $750 million, including $200 million for pollution control equip.

DC Line - The 400 kV DC (kilovolt direct current) transmission line delivers energy from Coal Creek Station in central North Dakota 436 miles to the Dickinson Converter Terminal near Delano, Minnesota. The line is part of the Coal Creek Project owned by Great River Energy.

DC Line Cost - The DC Line cost was $250 million including two converter stations.

Distance - Our bus-ride from Owatonna to Bismarck is 493 miles. Coal Creek is two miles from Falkirk Mine. It takes 12 minutes and six miles to drive there by road. Coal Creek is on Hwy #83 at mile marker #134 & Falkirk is at mile marker #136.

Easement Payments - Easement payments were approximately $17 million.

Employees - Coal Creek Station has 240 employees. Average age is 43. The average length of stay in ND is 15 years.

Energy Use - About 8% of the power produced is needed to operate the plant and mine.

Environment - $200 million has been spent to equip the plant with the best available technology to protect the environment. The vapor you see from the 650 foot stacks is really only steam coming out at 200 degrees.

Environment-Wells - There are 300 wells around the property to check the water quality on a regular basis.

Electric Motors - There are a total of 5,000 electric motors at Coal Creek.

Fly Ash - About 30% of the fly ash produced is sold for $19 per ton and used in concrete. Electrostatic Precipitators remove in excess of 99.5% of fly ash.

Generator - Generator output to the main transformer is 22,000 volts, Alternating Current (AC). The main transformer steps the voltage up to 230,000 volts AC, and it is sent out to the switch yard/converter station to be converted into 400,000 High Voltage Direct Current (HVDC) power before it is sent to Delano, MN to be converted back to AC power.

Generating Capability - 1,116 MW - Each turbine generator is rated 550 MW (megawatts).

Height - The height of the Steam Generator Building is 295 feet or 29 stories. You can see Underwood to the north and Washburn to the south. Both towns are seven miles away.

Largest Plant - Coal Creek is North Dakota=s largest power plant. There are ten power plants in this area.

Location - Underwood, ND. is the location of Coal Creek Station.

Ponds - Settling ponds are to settle out gypsum. The gypsum is sold as fertilizer.

Plant Area - The entire plant area sits on 3,370 acres.

Pulverizers - There are eight pulverizers in each unit, each capable of grinding 70 tons of coal every hour. Seven in each unit are needed for full load operation. Inside each pulverizer there are three grinding rolls, each weighing more than eight tons.

Scrubbers - Flue Gas Desulfurization (Scrubbers): Wet lime counter-current spray towers remove 90% of SO2 from 60% of the gas.

Start-up - Generator Unit 1 came on line in 1979 and Unit 2 came on line in 1980.

Steam Generators - The Steam Boilers produce 3.7 million pounds of steam per hour.

Transmission Line - It is less expensive to transmit electrical energy than to haul coal over a long distance. That is why the plant was located adjacent to the coal mine in North Dakota. To get the electricity from North Dakota to Minnesota, a 436 mile high voltage direct current (HVDC) transmission system was built.

Turbine-Generators - The turbine- generators are manufactured by General Electric. Each generator is capable of producing 550,000 kilowatts of electricity at 22,000 volts and 3,600 RPM. Each turbine is a tandem compound reheat Steam Turbine with double-flow low-pressure sections, containing 39 rows of blades arranged around the turbine shaft like a fan. The reaction of the steam passing through the blades causes the turbine shaft to rotate, which rotates a huge magnet inside a coil of wire in the generator to produce electricity. Steam enters the high pressure section of the turbine, causing the turbine blades to spin. As the steam gives up heat and pressure, it is returned to the boiler and reheated again. Then it passes through the low pressure sections of the turbine, exhausting its energy. Steam then enters the condenser where it is changed back into water and pumped back into the boiler again. At full load the generators generate the equivalent of 750,000 HP. The combined weight of stator and rotor is 500 tons.

Warehouse - The Warehouse has about $9.5 million worth in inventory and 22,000 parts.

Water Consumption - Water consumption is up to 14,300 gallons per minute; 15,000 acre/feet per year maximum. Coal Creek is a zero discharge plant which means that all waste water, which is 99% pure, is held in storage ponds and none is discharged back into streams, rivers, etc. The waste water is used to mix with the ash.

Water Source - Water comes seven miles from the Missouri River through a 32 inch underground pipe to a 35 acre storage basin at the plant site.

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