Liberal Govts tend to govern pragmatically.   That means, they will upset some of their traditional supporters at times and use political capital to help push decisions.

When Trudeau announced carbon taxes, you could almost predict that this would be one of the outcomes since the real purpose of the carbon tax is to mollify some of the environmental concerns.    In that sense, the carbon tax can be looked upon almost like a big marketing expense.    

Anyway, it remains to be seen whether Kinder Morgan will actually be built - but at least a decision has been made and now the court challenges and dealing will begin.