That was a threat from last March when Trump was actively threatening to annex Canada and the tariff wars were just starting.
It was an effective threat because the US is very dependent on Canadian electrical generation. And, the grid was never disconnected because Canada makes a lot of money selling electricity to the US.
Ontario is already talking about cutting off the US grid. Obviously changing voltage, frequency and maybe plugs(although the EU does not have a standard for that) would be a big change.
That was a threat from last March when Trump was actively threatening to annex Canada and the tariff wars were just starting.
It was an effective threat because the US is very dependent on Canadian electrical generation. And, the grid was never disconnected because Canada makes a lot of money selling electricity to the US.