By Dan Kraker

MPR, 90.1

Enbridge Energy is proposing its largest pipeline project ever to transport more Canadian tar sands heavy crude to the U.S., the third major oil pipeline expansion or replacement it’s planning across northern Minnesota.

The Calgary-based company this week proposed spending $7 billion to replace its 46-yeare-old Line 3 pipeline, which runs from near Edmonton to Clearbrook, Minn., on to Superior, Wis.

The 1,000-mile pipeline was originally built to move 760,000 barrels of heavy crude a day. But it now requires regular maintenance, and because of reduced pressure currently transports only 390,000 barrels a day. The replacement line would restore the pipe’s original capacity.

“You can think of this project as providing a needed buffer to deal with unplanned disruptions, maintenance, and additional scheduling flexibility that our shippers require,” said Enbridge Energy Partners President Mark Maki in a conference call with analysts Tuesday.

Company officials say without the replacement pipeline, Enbridge would need to spend $1.1 billion on maintenance by 2017, including $100 million on the U.S. side.

Environmental groups quickly objected to the expansion plan.

“Will this new pipeline ‘significantly exacerbate’ carbon pollution? Of course it will,” Sierra Club staff attorney Doug Hayes said in a statement. “Doubling the size of a pipeline that carries toxic, corrosive tar sands crude will require a full environmental review and will meet the same level of scrutiny and opposition as the other proposed tar sands pipeline projects.”

Hayes said Enbridge will need to apply to the U.S. State Department for a so called “presidential permit” for the Line 3 improvement, because it crosses the U.S.-Canadian border.

But Enbridge spokeswoman Lorraine Little said the company does not believe it needs an amended permit. She said their existing permit allows for maintenance of the line to restore it to its original capacity.

Enbridge also is planning to expand its Alberta Clipper pipeline that also runs to its hub in Superior, Wis. That line currently carries 450,000 barrels a day. Enbridge proposes expanding that to 800,000 barrels per day.

Little said the company is experiencing delays in acquiring the needed State Department permit for the Alberta Clipper line. The company initially expected that permit to be approved in mid-2014, but that now could take longer because of increased environmental scrutiny of projects like the Keystone XL pipeline that carry heavy crude from the Canadian tar sands region into the United States.

The company also has proposed a new pipeline called Sandpiper to carry oil from the booming Bakken fields in North Dakota across northern Minnesota. That project requires approval from the Minnesota Public Utilities Commission.

Enbridge officials say the company aims to complete the Line 3 expansion by the second half of 2017.