Interprovincial Pipelines are Federal Jurisdiction
Every Canadian observing the pipeline chatter going on right now should know this truth: pipelines that cross provincial borders, and pipelines for export, are indisputably FEDERAL jurisdiction in Canada.
This isn't a theoretical question, a philosophical debate, or an ideological perspective. It's not even a concept evolving judicially either. It's settled fact in Canada. Period.
It really makes you think because after all, he seems to be okay with turning a blind eye to open pit coal mining and coal exports in his own province (which the other doesn't criticize in support of resource development and jurisdictional respect) while he simultaneously blocks proven, safe, efficient transportation infrastructure of another source of fuel that has lower emissions intensity, is fully reclaimed when developed, with the vast majority extracted sub surface, and would benefit the whole country.
One might say that's not very neighbourly. 
Secondly, since the proposal is squarely in federal jurisdiction, the federal government absolutely has the power to ensure such infrastructure can get done. Don't let them tell you otherwise. The Liberals already proved it when they killed two others (Northern Gateway and Energy East) through veto and interference, and let the TMX private sector proponent get forced out because building was blocked by other levels of government and activists, precisely because this same federal government did NOT exercise all its tools and authority.