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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

Power lines demolished (KM) (*)

(*) 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).

  • Planning and consultation

    Terna's planning uses assessments based on digital thematic maps, mostly deriving from official sources (regional authorities, water concession authorities, monitoring agencies), which are organised in a large and constantly updated database. Since 2002, Terna has voluntarily brought forward dialogue with local stakeholders in order to identify shared solutions ahead of any consents process for new projects. Dialogue with local authorities, the Strategic Environmental Assessment (SEA) procedure in the Development Plan and public initiatives that address the members of local communities directly affected by the presence of new infrastructure, all contribute to the design of initiatives to mitigate environmental impact.

  • Design

    Choosing the route is the most delicate phase of the design process, as it determines the environmental impact of the entire development project.

    For this reason, notwithstanding the need to identify a route that makes it possible to operate and maintain the power line, Terna looks for design solutions that minimise land use, interference with areas of environmental, natural, landscape and archaeological value, as well as urbanised or built-up areas, and the related easements. Terna's design process includes the study of construction plans aimed at using existing roads or tracks to minimise the opening up of new access routes, especially in wooded or protected areas, and the assessment of problems relating to vegetation management. This entails the adoption of methods and tools to minimise the impact on biodiversity, such as optimising the height of pylons and their location. The drawing up of the Environmental Impact Study provides detailed information on the various components that help designers to turn the blueprint into an optimised project.
    Great attention is paid to minimising the visual impact. If this cannot be mitigated by means of precise and appropriate choices of location and/or by taking advantage of morphological features, the following actions may be taken:

    • Choice of pylons with reduced visual impact. In recent years, Terna has expanded the range of available pylons that may be used, with the introduction of new single-pole pylons with a low environmental impact (with an overall surface area of 10 square metres compared to 150 square metres for traditional pad/pyramid type pylons) and the design by internationally renowned architects of pylons that are more integrated into the landscape.


    Type of pylon Line Total
    Single pole 380 kV lines 498
      220 kV lines 43
      150 kV and 132 kV lines 2,244
      Minor 150 kV and 132 kV lines 798
    “Germoglio” and “Foster” Trino - Lacchiarella 6
      Tavarnuzze - Casellina 9

    • Use of underground cables, which eliminates or reduces the typical visual impact of overhead lines, is perceived as negative especially in built-up areas. Underground cables, although appreciated and requested by local authorities, pose technical and financial problems. Underground lines can only be built for a limited number of consecutive kilometres, are less reliable than overhead power lines over time and require much longer repair times in the event of a malfunction. For this reason, they often do not guarantee adequate security for the electricity system and continuity of service. Underground cables also have a greater impact during the construction phase - for example, in terms of road works - and higher construction costs.
  • Execution: site operations

    Terna manages the impact of its construction sites on the environment via the operating manual, "The management of environmental aspects during infrastructure construction", in line with the Group's Environmental Policy and existing regulations.

    This operating manual introduces the role of the environmental contact, a person tasked with monitoring the environmental requirements contained in the EIA Decrees and in the opinions of authorities with responsibility for the environmental, as well as compliance with legal obligations, also with reference to the activities carried out by contractors. The environmental contact also monitors the indicators set out in ISO 14001 certification, relating to complaints/reports, environmental accidents, waste, and the consumption of energy and natural resources.

    Special attention is paid to the identification of areas and access roads to sites which, if compatible with technical and design requirements, are located in areas of reduced natural importance. On completion of the construction work, Terna restores the areas concerned to their original state.

    If these areas regard natural or semi-natural habitats, in addition to the normal restoration works, specific interventions are implemented, based on natural engineering techniques, to provide favourable living conditions for animal species ( These include re-naturalisation, aimed at creating environments suitable for species or plant and/or animal communities (habitat reconstruction), the replanting of native live plants, which do not require irrigation or special fertilisation or the use of materials, even if only inert.

    Terna's environmental policies, which are also applied at construction sites, have been drawn up in accordance with the applicable environmental laws and the ISO 14001 standard. These include such aspects as prevention of groundwater contamination and limitation of damage to vegetation, the management of accidents, the minimisation of atmospheric and noise pollution, the use of vehicles, and the proper management of waste and excavated earth. Internal audit campaigns regarding construction sites enable any deviations from the Company's environmental policies to be identified.

  • Mitigation and Compensation

    In compliance with requirements received during the consents process, or voluntarily, Terna adopts mitigation measures to reduce the impact and improve the integration of electricity infrastructure within local areas.

    Specifically, in its design process the Company gives priority to line locations that take advantage of natural morphological features, creates camouflage systems for its electricity substations, and makes use of natural engineering techniques for habitat reconstruction and the stabilisation of slopes and embankments. With regard to the new overhead power lines, other mitigation measures consist of camouflaging pylons with paint and the use of coloured insulators that enable the new lines to blend in better with the landscape.

    Offsetting, which is usually of a technical and/or environmental nature, is specified by the authority issuing the consents. In the preparation of a project proposal - together with national, regional and local regulations - this constitutes a "binding standard" for the detailed design and execution of the project.

    In most cases, offsetting accentuates or better defines the mitigations proposed in the environmental impact study, or imposes new offsets on the advice of specialist bodies (government authorities, the grantors of water concessions, park authorities, etc.). Offsets may take the form of compensation. If the competent authority does not consider a residual impact to be sufficiently mitigated, it takes into account another initiative located elsewhere capable of offering environmental compensation.