Rationalisation consists in complex work involving several segments of the grid at the same time, and often including the elimination of some portions in conjunction with the construction of new lines.

The grid is rationalised mainly by:

  • replacing some lines with superior ones, for example new 380-kVi links instead of a larger number of lower-voltage lines;
  • eliminating grid segments whose utility is nil or negligible after new construction has upgraded the grid;
  • avoiding upgrading infrastructure, mainly lines, that has reached the point of saturation by installing new grid components, such as, for example, stations.

Especially in the vicinity of cities, rationalisation enables the Company to solve problems connected with the presence of electric infrastructure in areas undergoing urbanisation. In the overall rationalisation work included in the development plan, demolitions far exceed new constructions, with a net positive effect in terms of freeing areas from the presence of electric lines. The dismantling of stretches of line made possible by the construction of new lines constitutes the most significant contribution to the benefit of the environment stemming from grid development.

Laying cables underground eliminates or reduces the negative impact on the landscape that is typical of overhead lines. For this reason, local institutions often request underground lines as the first option for constructing new ones. Actually, underground lines involve a number of technical and economic problems. They are less reliable over time than overhead lines, take much longer to repair if something goes wrong, require appropriate roads while under construction, and cost from five to ten times as much.   

Reclassification provides for the conversion of existing electric lines to a higher voltage through the construction of new conductors and supports. This work may entail the replacement of the old supports by ones that are larger and thus occupy more space, as happens, for example, when a 130-kV line is reclassified as 220-kV. With respect to the construction of a new line, however, reclassification has the advantage of generally using already existing infrastructure corridors, thus avoiding the encumbrance of new portions of land.

Enhancement is aimed at reducing the exposure of people to electro-magnetic fields by, for example, raising line supports. Upgrading can also involve shifting the route, while at the same time dismantling stretches near densely inhabited areas or their reconstruction in cable, in this case with a positive effect on the landscape to boot.