EN26Terna’s plants are disseminated throughout Italy in a grid that extends for nearly 57,000 kilometers. The grid’s relation with the surrounding natural environment and its impact on biodiversity take on different characteristics during the construction of new lines and the operation of existing ones. During the construction stage, the impact on biodiversity is connected with the activities on the work site: the opening of passageways in order to build the towers, excavation of the earth, and the removal of left-over materials. The construction of new EN12lines and stations requires special attention if it takes place in the vicinity of or inside protected areas.

Once the line has been constructed, it has a two-fold relationship with biodiversity. On the one hand, the route of the line can be a factor of growth for biodiversity and protection for several species. For example, when lines cross large open areas or extensive areas of grain monoculture, the towers and their bases represent “islands” of concentrated biodiversity. Tower bases – especially the larger ones that support high-voltage lines – are the only zones spared from intensive agriculture, with its land transformation and use. These are places where spontaneous grasses and brambles flourish in which wild rodents find shelter, since their den systems are not periodically destroyed by plowing. They are also places with concentrations of predators of the rodents, i.e. birds of prey. Birds, especially rapacious ones, commonly use electricity lines and their towers as both posts for observing the surrounding area and structures for nesting.

On the other hand, lines have potentially negative effects on biodiversity, that regard birds in particular. The risk of electrocution should not concern Terna’s lines, since it is connected with the narrow space between the typical wires of low- and medium-voltage lines, which can electrocute birds – especially large ones – that cross their route. However, high-voltage lines can entail the risk of collision. The actual occurrence of collisions depends on the density of the birdlife and the frequency with which birds fly in the vicinity. The important factors in this regard are the routes of migratory bird – which are especially important in Italy, a bridge between Europe and Africa – the location of wetlands in the area, and the presence of protected areas, reserves and parks.

A radar for migratory birdsEN26

For the construction of the Sorgente-Rizziconi line, whose route includes an overhead part in the proximity of the Strait of Messina, for the first time in Italy, Terna has experimented with using radar to monitor birdlife passing by the future route of the line. This particular attention is justified by the importance of the Strait of Messina for migratory birds who arrive in Sicily from Africa and then travel on to the peninsula through the strait in the area around Scilla. Observations were carried out for two weeks during the migration in spring 2010.

The radar system punctually registered the number of crossings, the altitude and the flight direction of the birds in transit. The experiment scientifically measured the potential impact of the projected line on the migratory area of the trans-Saharan birdlife by clearly identifying their flight pathways and altitudes. This made it possible to avoid that the lines involved significant risks for migratory birds.

The new line will play a principal role in developing the “green” energy sector, and will bring about significant benefits for the electricity system; it will, in fact, allow more wind farms, which are experiencing rapid growth in Sicily and in all of southern Italy, to connect to the Sicilian grid, which will make it possible to export renewable production (wind and solar) of over 700 MW from the island to the mainland.