ROSEMOUNT, Minn. - The thick plumes of steam rising from the Flint Hills Resources Pine Bend Refinery can be seen for miles on Hwy. 52 south of the Twin Cities on a cold winter day.
Pine Bend was built in the 1950s to handle crude oil from western Canada, then tapped through conventional drilling in central Alberta.
But beginning in the 1960s and expanding greatly in the 1990s, Canadian oil companies have mined crude in the northeastern Alberta oil sands - thick, tar-like deposits mixed with sand.
This "feedstock," or unrefined oil, is separated from the sand and sent by pipeline to refineries in the northern United States.
Other Midwestern refineries are bigger - the Whiting, Ind., facility near the shore of Lake Michigan can process about 400,000 barrels per day - but Pine Bend is the largest refinery this far north.
It's capable of churning through 325,000 barrels of crude a day, said Gary Ista, a Pine Bend production supervisor.
In comparison, the Marathon Oil refinery in St. Paul Park can handle 75,000 barrels a day, the Murphy Oil refinery in Superior, Wis., about 45,000 barrels a day.
Pine Bend is owned by Flint Hills Resources, a subsidiary of Koch Industries, one of the largest privately held companies in the world. Both are based in Wichita, Kan.
The fenced-in refinery covers 1,000 acres and has about 10 miles of roads, plus 2,000 to 3,000 miles of intertwined pipe.
The refinery has several security entrances, and cameras monitor the facility and any vehicles using the frontage road alongside it.
Outside the fencing is about 1,500 acres of natural areas and another 1,500 acres in agricultural use.
The refinery employs about 900 people, many from western Wisconsin. Another 500 to 2,000 contractors may be on site at any given time, doing maintenance or construction.
"It requires a lot of maintenance," said Jake Reint, refinery communications director, "because of the weather and the feedstock we use, which is very corrosive."
That heavy crude from Canada's oil sands, which makes up 80 percent of what Pine Bend processes, is high in sulfur and contains about 40 percent asphalt per barrel, compared with 15 percent for light crude.
"Its physical properties are denser, which make it more challenging to refine," Reint said. A federal law also requires that refiners produce ultra-low sulfur fuels
Unlocking what lies inside such crude requires more energy: The refinery uses about 120 megawatts of electricity a day, Ista said. That's enough to serve 91,000 homes, said Neil Kennebeck, director of planning services for Dairyland Power Cooperative.
"We're Xcel Energy's biggest customer," Reint said.
Still, the refinery has been recognized for energy conservation programs and has among the lowest emissions per barrel in the industry, down more than 50 percent in the past 10 years despite expanding production, he said.
Along with gasoline and diesel fuel, the process yields asphalt, carbon dioxide for food processing, propane and butane gas, sulfur for manufacturing, Reint said.
The refinery even supplies the Minneapolis St. Paul International Airport with jet fuel by pipeline.
Huge drums called "cokers" further wring out gasoline and other products from the 40 percent asphalt, including petroleum coke for electric power generation.
"Virtually every drop of a barrel of oil gets used as a product," Reint said.
Through this, Pine Bend produces 30 percent to 40 percent of Wisconsin's transportation fuel, Reint said,
"We provide a significant amount of the gasoline in Wisconsin," he said. "Kwik Trip is a large customer of ours."
The La Crosse-based company has 110 tanker trucks and 55 drivers who have a nonstop cycle transporting gasoline from the refinery to its 363 convenience stores in Wisconsin, Minnesota and Iowa.
TUESDAY: On the road with a Kwik Trip tanker truck.