I believe that long distance transmission lines are made of aluminum, not copper. They also often contain several strands of steel wire to strengthen then. While copper is a better conductor, it’s weight/conductivity ratio is higher than that of copper. Copper is used in the step-up and step-down transformers at either end. But the bulk of materials used is aluminum.
Not meaning to second guess ya’ Brian. Just trying to maintain accuracy in order to maintain credibility.