When U.S. President Donald Trump’s top trade representative outlined conditions Canada would need to meet with a mandatory review of the Canada-U.S.-Mexico Agreement (CUSMA) looming, familiar issues like dairy supply management made the list.

Less familiar was a pointed reference to Alberta’s electricity system, with U.S. Trade Representative Jamieson Greer telling Congress that Alberta must revisit its “unfair treatment of electrical power distribution providers in Montana.”

In the view of representatives of Big Sky Country, Alberta’s rules sometimes block Montana electricity from being sold into Alberta, which they say hurts their power producers and discourages cross-border transmission investment. Alberta, meanwhile, says it isn’t treating Montana any differently than it does its Canadian neighbours.

Last year, the Office of the U.S. Trade Representative listed Alberta’s non-profit electrical grid operator, the Alberta Electricity System Operator, or AESO, as a trade irritant.