Montana-Alberta tie line now fully operational

MATL Alberta inter-tie connects Montana and Alberta via a 345 km transmission interconnection, enabling cross-border electricity import/export capacity (~300 MW), strengthening AIES grid reliability and supporting wind integration without costs to Alberta consumers.

In September 2013, the Montana-Alberta Tie Line MATL became fully operational. MATL is a 230 kilovolt “merchant inter-tie”—a transmission line owned by private investors Enbridge—that connects the Alberta Interconnected Electric System AIES to the NorthWestern Energy power grid system in Montana.

MATL is Alberta’s first merchant inter-tie and the province’s first interconnection to the U.S. electricity market. Alberta electricity consumers will not bear the cost of constructing or operating this line.

Inter-ties are transmission interconnections between neighboring electric systems that allow power to be imported and exported. Alberta currently has two other interconnections with neighboring jurisdictions—an inter-tie to Saskatchewan capable of importing and exporting 153 megawatts MW, and a larger inter-tie to B.C. that, under current reliability limits set by system operators, can transfer 700 MW for import and 735 MW for export.

MATL has the capacity to import and export approximately 300 MW between Montana and Alberta, according to a project analysis by a Montana agency. The line is 345 km long, with the Canadian portion stretching approximately 123 km between the U.S. and the new Picture Butte substation in the Lethbridge area.

The addition of MATL to the AIES will bring more diversity to Alberta’s electricity supply and will help support the development of wind generation in the region.

The new line will be primarily used to import electricity from Montana. Initially there will be few exports on it due to limited access from Montana, where transmission proposals are advancing, to the Pacific Northwest’s connection. Alberta has been a net importer of electricity for 16 of the last 17 years.

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