The Minnesota Department of Commerce will appeal the approval of Enbridge's controversial new oil pipeline across the northern part of the state.

The Minnesota Public Utilities Commission (PUC) approved Line 3 for a second time in February, and Wednesday is the deadline to challenge the decision before the Minnesota Court of Appeals. The Commerce Department said late Tuesday it would appeal — as it did after the PUC first approved in June 2018 the pipeline, a replacement for the deteriorating Line 3.

The first appeal was under former Gov. Mark Dayton. This appeal is the first under Gov. Tim Walz's administration.

Calgary, Alberta-based Enbridge, in a statement, said "it is disappointing that the Walz administration has chosen to pursue an argument that has been in front of the PUC numerous times and failed every time." The appeal "is not supported by evidence or Minnesota law."

The Commerce Department said in its filing Tuesday that the PUC committed a "legal error" in its evaluation of the accuracy of Enbridge's long-term oil demand forecast because the company never submitted a proper forecast. Also, the department said the PUC shifted the burden of proof from Enbridge to the department itself to show that long-term oil demand would decrease.

The first appeal was based on similar reasoning.

Enbridge said the new Line 3, which would transport Canadian oil to Superior, Wis., would be safer and restore the full flow of oil, while opponents said that oil spills could foul a new region of Minnesota's lake country and contribute to climate change.

Several environmental groups and Indian bands also are likely to appeal the PUC's decision.

The Minnesota Court of Appeals, in the first appeal, sent the issue back to the PUC, saying the environmental impact statement (EIS) for the project was deficient. The Commerce Department redid a small part of the EIS, and the PUC reapproved the EIS and then the project for a second time. The Commerce Department serves as research arm for the PUC, as well as representing the public interest before the commission.

Mike Hughlett • 612-673-7003