Often it is not so much the construction of a new line as the manner of its implementation that gives rise to debate. In Switzerland, low- and medium-voltage lines are usually laid underground. The impact on the soil of this type of cabling is relatively low, and the costs are manageable. On average it is assumed that the cost of laying low-voltage lines (400 V) underground is equivalent to the cost of an overhead variant. Per linear kilometer, medium-voltage lines (16 kV) cost twice as much, and ultra-high voltage lines (125 kV) three or four times as much.

Besides voltage, the number of existing parallel systems, topography and geology of the route, and in particular the transport capacity of the line play an important role in the decision whether to lay a line underground or above ground. The rule is: the greater the capacity, the more difficult it is to lay the required infrastructure underground.

With a capacity of no less than 4,000 MW, the lines planned between Yverdon and Galmiz and between Chamoson and Ulrichen are veritable electricity highways.