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In terms of environmental impacts, Terna's most significant activities regard not so much the use of natural resources or the emission of pollutants, but rather the physical presence of power lines and power stations and their interaction with the surrounding natural and man-made environment.

Therefore, the most significant environmental aspects of Terna's activities, in addition to the occupancy of land, are the visual impact on the landscape, electric and magnetic fields, and the effect of power lines on biodiversity, especially birdlife. Greenhouse gas emissions and hazardous waste, however, are relevant within the context of operations.

The construction of new lines responds to the technical needs of the electricity system – such as removing congestion and eliminating risks of overload – and to increasing energy production and consumption, which accompanies the economic growth of specific areas or of the entire country. The environmental actions preceding the coming into operation of grid development investments are described below

  • Planning

    From the grid development and adjustment planning stage, Terna has made use of assessments based on digital thematic maps, mostly from official sources (Regions, River Basin Authorities, the company Audit System), organised across an extensive database that is constantly updated.

    Interventions with which Terna can reduce the impact of power lines on the environment can be attributed to two categories

      1. Rationalisation: complex work which involves several grid components at the same time, consisting of replacing some plants with better systems, eliminating the parts of the grid which are of negligible use following new constructions, or adding new grid elements to avoid having to upgrade saturated lines. In 2017, 98 km of lines were demolished. In the 2010-2017 period, 1,002 km of lines were demolished.
      2. Reclassification, that is converting existing power lines to a higher voltage by installing new conductors and pylons in place of the existing ones. This can involve replacing old pylons with larger ones, which therefore take up more space. Reclassification, compared with constructing a new line, has the advantage of generally using pre-existing infrastructural corridors, avoiding taking over new land

    (*) The figure for 2016 is exceptional due to the demolition of over 200 km of obsolete power lines in Valtellina, which had been in preparation in previous years. After adjusting for this removal, demolitions amounted to approximately 80 km, in line with previous years (approximately 100 km per year).

  • Consultation

    Since 2002 Terna has voluntarily brought forward discussions with local communities to the project planning stage of its Development Plan. The dialogue with local institutions at the consultation stage and the Strategic Environmental Assessment (SEA) procedure of the Development Plan and the public initiatives for citizens of the local communities that are directly affected by the move to new infrastructures, offer indications for mitigating the environmental impact at the design stage.

  • Design

    The search for the route for the construction of a power line is the most delicate design stage because it is the choice of route that can mitigate or affect interferences with the surrounding landscape and community.

    Therefore, Terna researches design solutions that minimize, as far as is possible, soil consumption, interference with areas of environmental, natural, landscape and archaeological value, whether urbanised or urban development areas, and the sacrifice required by the properties involved. This is with the exception of where a route is needed to enable the regular operation and maintenance of the power line. During the design stage Terna considers problems related to vegetation cutting right from the initial stages, adopting methods and tools that aim to reduce interference to a minimum:

    • Optimising the height of pylons and their locations
    • Studying site plans with the aim of using existing roads or routes, reducing the creation of new routes, especially in wooded or protected areas

    Great attention is paid to minimising visual impact which, where it is not mitigable using precise, suitable location choices and/or taking advantage of morphology, can make use of the following actions:


    • Choosing pylons with a reduced visual impact. In recent years Terna has expanded the available alternatives, also turning to new “single-stem” pylons with a low environmental impact (occupying 10 square metres of ground surface compared to the 150 square metres for truncated pyramidal pylons)
    •  Use of underground cables which eliminates or reduces the visual impact typical of overhead stretches of power lines, which are negatively perceived, especially in built-up areas. However, burying cables, although appreciated and requested by local institutions, is problematic from a technical and economic point of view: underground lines are less reliable over time than overhead lines and require more time for repairs in the event of a malfunction. For this reason, they often do not ensure adequate security for the electricity system or service continuity. In addition, buried cables cause a greater impact in the construction stage – for example, in terms of road traffic – and much higher construction costs (from five to ten times the cost of an overhead line).
  • Construction

    Terna manages the environmental impacts of its construction sites via the "Management of the Environmental Aspects during Plant Construction" operating guidelines, in line with the Group’s environmental policy and current legislations, adopted in February 2016.

    The main changes introduced include:

    • the environmental officer, a role which is tasked with overseeing the environmental requirements (contained in the EIA Decrees and the opinions of environmental bodies) and respecting legal obligations, also in reference to the activities conducted by contractors
    • environmental monitoring of the indicators provided by ISO 14001, (conducted under the supervision of site assistants) concerning complaints/reports, environmental accidents, waste and the consumption of energy and natural resources

    Particular attention has been paid to identifying construction site areas and access routes, which are located, where compatible with the technical and planning needs, in areas of less naturalistic value. When the project is complete, Terna provides for the restoration of the sites involved back to their original state. 

  • Requirements

    Requirements, usually technical and/or environmental in nature, are indicated by the authorising body and, in conjunction with national, regional and local legislation, constitute a "binding regulation" for the proposing party for the executive planning and construction of the work itself.

    In most cases they accentuate or better define the mitigations proposed in the Environmental Impact Study or impose new ones on the advice of specialised bodies (Superintendencies, River Basin Authorities, Park Authorities, etc.).

  • Mitigation and Compensation

    In compliance with the requirements expressed during the authorisation procedure and/or on a voluntarily basis, Terna adopts mitigation measures to reduce the impact, and/or improve integration into the environment, of the electrical structures.

    In particular, Terna creates systems to hide its own electrical substations from places frequented by tourists or those of landscape-environmental interest; redevelops assets with cultural importance; during the design phase prefers to locate lines where they take advantage of natural morphology and makes use of naturalistic engineering techniques for restoration after demolitions, reconstructing habitats and stabilising slopes or embankments.

    If the mitigation measures are not sufficient to reduce the interference to insignificant levels, environmental offsetting measures are adopted, that is environmental regeneration or habitat reconstruction work on areas close to the power line such as balancing out the trees cut along the lines in the projects by planting individual trees of the same species over equivalent areas.

    In 2017, two redevelopment and vegetation rehabilitation initiatives were carried out in areas affected by the construction of electricity infrastructure and five interventions were planned. These will be carried out using natural engineering techniques. In 2018, an electricity substation camouflaging project, which was designed in previous years, is being carried out.