Management of impacts on biodiversity

Terna manages its impacts on biodiversity with a series of integrated instruments that consider such impacts right from the planning stage and, whenever necessary, the adoption of appropriate mitigation and compensation measures.

The approach is primarily preventive. Beginning in the planning stage, Terna considers the need to preserve the environment by seeking solutions agreed on with local governments regarding the location of its electricity infrastructure. Like other environmental variables, biodiversity – and in particular the presence of protected areas – therefore represents an important input in the sustainability-based planning of grid development. The biodiversity features of the areas that could potentially host new infrastructure are carefully studied. The information collected becomes part of the criteria determining the final route and is available in the parts of the Environmental Report containing regional details that accompany the Grid Development Plan.

This approach was confirmed in the memorandum of understanding signed by Terna and the WWF (see the box below), which provides for, among other things, the incorporation of environmental criteria consistent with the WWF’s conservation strategy in the planning of new lines.

Completion of Terna’s works in three WWF OasesEN13

oasidipadule.jpgStarted in 2010, the first three environmental restoration and mitigation projects envisaged by the strategic partnership between Terna and WWF Italia and prepared in collaboration with WWF Research and Planning, were implemented and presented to local institutions and media.

In spring 2011, following the occasional suspension of activities at the worksite so as not to interfere with the nesting season, the works in the Tuscan Oases of Stagni di Focognano, on the Florentine plain, and Padule Orti-Bottagone, in the municipality of Piombino (Livorno) were completed.

In Focognano, a lake Oasis that spans 35 hectares and is only 10 kilometers from the historic center of Florence, the presence of two HV electricity lines with two supports placed directly in the pond, and two at the edge of the area, has oriented the works in the direction of mitigation of impact on birdlife. high voltage cables are not easily seen and pose a potential danger to birds in flight who use this Oasis as a stop-over, such as the blackwinged stilt, the red heron, the little egret and the little bittern. In order to minimize such risk, Terna has constructed actual road signs for birds that cover over 1000 meters of electricity line. The installation of 108 “anti-collision spires” was carried out by specialized technicians thanks to a spectacular helicopter maneuver. These are special colored visible spiral-shaped devices wrapped around guard- wires whose purpose is to avoid collisions, while the hissing of the wind also makes them effective at night. In Focognano, Terna has also set up artificial nests on some pylons, complete with webcams, in order to encourage reproduction of Kestrels and allow for monitoring.

With respect to the Padule Orti-Bottagone Oasis, the WWF-Terna goals are to significantly increase the naturalistic potential of the area together with the strengthening of infrastructures for the management, fruition and monitoring of the species present. In this area, which includes six different habitats of community interest, and which is divided in two by the provincial road, the first ever “condo” for birds in Italy was built. It is a special watchtower where 154 nests of different shapes and sizes have been placed and which welcomes, apart from visitors and birdwatchers, martins, sparrows, swallows and swifts. Only a few months after the installation of the condominium, 5 couples of Italian sparrows and 4 couples of starlings nested and all the species arriving from Africa that the “houses” are intended for (martins, swallows and swifts) have already gone inside and surveyed the special structure, and may nest there in the upcoming seasons. As a result of this structure, Orti Bottagone was awarded the prize of “Most Beautiful Oasis” at the end of 2011 by EBN Italia, the Italian Bird Watching Organization for the promotion and enjoyment of oases and nature reserves.

Terna also built in Orti-Bottagone a watching post, a watchtower, an underpass that guarantees visiting continuity despite the provincial road that cuts across the Oasis and new paths for exploring the beauties of the area, including a special pathway on piles, shielded by a wall with slits for enjoying walks only a few centimeters from the water without disturbing the flamingos, blackwinged stilts, teals and cormorants stopping in the marsh.

Terna’s initiatives in these two Tuscan oases were presented to the citizens, institutions and local media at an event organized by WWF Italia in the Palazzo Appiani in Piombino, which was followed by a guided tour of the Orti Bottagone Oasis. The meeting in Piombino was also an opportunity to present video and hardcopy materials (brochures and maps of the Oasis) which were prepared for visitors to the Stagni di Focognano and Orti-Bottagone Oases.

In the fall, the works on the third WWF Oasis, the Sicilian Torre Salsa (Agrigento), were concluded and it, too, was chosen because it is typically representative of Italian territory.

The main objective of the project was to increase the use of the Oasis in terms of nature tourism and didactic and scientific research activities. The result is an outfitted overlook facing the sea from which one can admire the hundreds of egrets, herons, spoonbills, the European honey buzzard, and cranes who in the spring and fall pass through one of the most important migration routes on the peninsula, as well as the peregrine falcon who nests on the imposing rocky sea cliffs along the coast. An open-air green room was created, protected by a tensioned structure in wood and cotton, fully removable, as well as a pathway with benches, informative lecterns and boards so that everyone can discover and enjoy the incredible variety of life that the Oasis hosts.

Terna wanted to contribute to better management, surveillance and monitoring of the area by strengthening the physical and technological infrastructures (fences, railings and a system of closed circuit cameras) that will help to protect it from fires, poaching, littering or straying off-trail, which are the main threat factors for this delicate ecosystem.

In November, the work undertaken in the Sicilian Oasis of Torre Salsa were presented to the citizens, the institutions and local media at an event hosted by the Province of Agrigento.

Once this first plan has been completed, the agreement between the WWF and Terna envisages restoration and environmental requalification projects in the Gran Sasso National Park and Monti della Laga in Abruzzo, as well as the Pollino National Park in Calabria. In both cases, upgrading of the National Transmission Grid will take place, with the subsequent removal of stretches of lines, which is an interesting opportunity for environmental requalification of the old line routes. The environmental restoration works will begin once the removal activity has taken place.


In spite of the measures adopted in the planning stage, there may be interference between a given infrastructure component and several species or habitats. To reduce such interference to a minimum, measures of environmental mitigation are adopted during both its construction and its operation. In the event such measures are not sufficient to reduce the interference to levels of little significance, environmental compensation measures are adopted, i.e. actions in areas near the electricity lines.

The main mitigation and compensation measures involve:

  • environmental restoration consisting in the construction of naturalistic engineering works to regulate the surface outflow of meteoric water and thus control the phenomenon of soil erosion;
  • reforestation, through the planting of native species of trees and shrubs belonging to the vegetation of the area;
  • turfing by sowing seeds belonging to native species together with natural fertilizers and adhesives that help them take root. The use of native species prevents the phenomenon of floristic pollution via the introduction of species that are extraneous to the environment;
  • EU13compensation, i.e. offsetting the cutting down of trees along the planned lines by planting trees of the same species in equivalent places.EN13

With regard to the species of flora and fauna potentially involved, see the 2011 Environmental Report (published in the “Electricity System” section of Terna’s website).

During the construction of infrastructures, the habitats and species of the flora and fauna concerned are monitored. This is to check the actual appropriateness of the mitigation and compensation measures adopted in order to constantly assess their effectiveness and, if necessary, to make corrections. Specifically, environmental analyses are performed before construction; the data obtained are then compared to those from samples taken subsequently in order to promptly identify the appearance of any signs of deterioration.

As far as existing lines are concerned, Terna has tried out systems of mitigation regarding in particular the interference between lines and birdlife, which are described in the following section.

Terna is also investigating the possibility of using the lines of the NTG to support environmental monitoring. The installation of specific sensors on pylons would enable the implementation of programs for environmental data collection agreed on with local governments and park agencies. In this way, in addition to expanding the range of potential uses of its transmission infrastructure, Terna could make a significant contribution to the monitoring and management of biodiversity and the environment.

Masking the power stations in Chignolo Po and MaleoEN13

Following the construction of the power stations in Chignolo Po and Maleo, work was undertaken to mask the infrastructures through the use of natural engineering techniques.

The works concerned the perimeter area of the power station (nearly 30 sq m) and included planting and hydro seeding, with the two-fold objective of consolidating the land and masking the electricity infrastructure. In addition, native trees and shrubs were transplanted, such as, for example, four oak trees at the Chignolo Po station.

Works commenced September 2011, upon the definitive closure of the civil work site, and were terminated in November 2011.

For the next three years the plants will be inspected to ensure they have rooted, and general maintenance will be performed.


Studies on electricity lines and batsEN14

Interest in bats is on the rise. The UNEP Convention on Migratory Species and the European Agreement for the Protection of Bats (EUROBATS) celebrated 2011 as the European Year of the Bat and 2012 as the International Year of the Bat.

At present, however, there are no studies that discuss the effects electricity lines might have on bats, and what mitigating measures could be taken.

pipistrelli.jpgTerna has started research with the goal of:

  • describing what aspects of bat ecology could be affected by possible interaction with high voltage (HV) and extra high voltage (EHV) lines;
  • analyzing the literature on a national, European and international level concerning the subject and other potential problems connected thereto;
  • going into depth on the subject by consulting with international experts in the field;
  • providing technical charts concerning the biology of species potentially affected by the construction of new HV and EHV lines.

Through bibliographic research and consultation with international professionals and experts in the sector, the study went into depth on the biology and ethology of the species.

An in-depth examination showed that the subject matter has not been developed yet in Europe and no data exist in this regard.

The study concluded that as far as bats are concerned, HV and EHV electricity lines do not pose obstacles for them. In fact, the examination excluded the possibility of collisions, or interference with hunting, flight or migration. With respect to the loss of habitat, a catalogue containing possible mitigating actions that can be undertaken has been proposed. Such actions, after adjustment to tailor-fit exact needs, can be included into future Environmental Impact Studies. For each species of Italian bats, a file has been prepared that summarizes the distribution, the ecology of the species, potential impact and an analysis of flight in relation to the presence of different supports.

Of special interest is how the pylons are used, in particular how the space between the pillars of the pylon and the wall of the nesting house for birds of prey is being used by bats as a daytime shelter, first discovered in 2011 by ornithologists who collaborate with Terna.


Recovery and restoration of building site areas in Val D’Ossola SudEN13

Within the upgrading of the electricity grid in Val d’Ossola Sud, works have been undertaken for the restoration, mitigation and environmental compensation of the areas affected by the works.

The works, which were carried out between March and April 2011, provided for:

  • the forestation of the areas through the planting of dense, tall shrubbery that have a fast growth rate;
  • inspection and pruning of volunteer plants and exotic invasive plants around the areas affected by the forestation.

The choice of planting shrubs was determined also by the desire to have a type of tree that reaches a maximum adult height of 5/6 meters, so as not to interfere with the line cables.