Reducing the environmental impact

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EN26To reduce the impact of electricity lines on local communities and the environment, Terna can implement a series of solutions, which are described below.

Reducing the environmental impact

To reduce the impact of electricity lines on local communities and the environment, Terna can implement a series of solutions, which are described below.

Measures on the grid

Upgrading is complex work, which involves several grid components at the same time and often includes the dismantling of some grid segments and the construction of new lines.

Upgrading work consists mainly in:

  • replacing plants with more advanced ones, such as, for example, introducing new 380kV connections to replace a larger number of lower-voltage lines;
  • eliminating parts of the grid that are useless, following the construction of new infrastructures representing an upgrade;
  • integrating new grid components, for example stations, to avoid having to upgrade saturated lines.

When upgrading is possible, the construction of a new plant may lead to the reduction of the space occupied by electricity lines, because of the removal of the old lines. Especially in the vicinity of cities, upgrading represents a solution to problems connected with the presence of infrastructures in areas that are being gradually urbanized. Overall, in the upgrading work provided for by the Development Plan, infrastructure demolition greatly exceeds construction, with a net positive effect in terms of freeing the local communities from the presence of electricity lines. The demolition of stretches of line made possible by the construction of new lines represents the most significant contribution in favor of the environment entailed by the development of the grid.

Laying cables underground eliminates or reduces the negative impact on the landscape that is typical of the overhead stretches of lines. For this reason, local institutions often request underground cables as their first option for the construction of new lines. Underground cables actually have a number of technical and economic drawbacks. They are less reliable over time than overhead lines and take much longer to repair in case of malfunction. For this reason they often do not adequately ensure the security of the electricity system and service continuity. Furthermore, underground cables imply a greater impact in the construction site stage, i.e. in terms of road systems, and entail construction costs that are higher than those of overhead lines (normally five to ten times).

Reclassification includes the upgrading of existing electricity lines to a higher voltage through the construction of new lines and towers to replace the existing ones. This work may entail the replacement of the old towers with larger ones that occupy more space, as occurs when, for example, a 130kV line is upgraded to 220kV. However, with respect to the construction of a new line, upgrading has the advantage of generally using already existing infrastructure corridors, thus avoiding the occupation of new portions of land.

Enhancement work aims at reducing the exposure of the local population to magnetic fields (See in this regard the box on “Electric and magnetic fields: the legal limits”), by for example, using higher pylons. Enhancement work may also include changing the corridor, while at the same time dismantling stretches near clusters of population.

 

Electric and magnetic fields: the legal limits

The main reference values for the emission of electric and magnetic fields currently provided for by the law (Minister’s Decree of July 8, 2003) are the following:

  • exposure limits: in case of exposure to electric and magnetic fields at a frequency of 50 Hz generated by electricity lines, the limit is 100 microteslas for magnetic induction and 5 kV/m for the electric field, understood as effective values;
  • values of concern: as a precautionary measure of protection from possible long-term effects connected with exposure to magnetic fields generated at the grid frequency (50 Hz), in children’s play areas, homes, schools, and places where people stay for at least four hours a day, the value of concern for magnetic induction is 10 microteslas, understood as the average over 24 hours in normal operating conditions;
  • quality objectives: in planning new electricity lines near children’s play areas, homes, schools, and places where people stay at least four hours a day and in planning new settlements and areas such as the aforesaid in the vicinity of electricity lines and installations already present, in order to gradually minimize exposure to electric and magnetic fields generated by electricity lines operating at a frequency of 50 Hz, the quality objective is set at 3 microteslas for the value of magnetic induction, understood as the mean value over 24 hours in normal conditions of operation.

The values of the three parameters, and in particular the value of concern (10 microteslas) and the quality objective (3 microteslas) show that Italian legislation has adopted the precautionary principle expressed by article 15 of the Rio Principles. Compliance with the law in its activities implicitly entails Terna’s adoption of the same principle.

 

The online thematic mini-site on electromagnetic fields (EMF)

campi-elettromagnetici.jpgThe “Sustainability” section of the website www.terna.it has been expanded to include a mini-site dedicated to electromagnetic fields (EMF), which provides accurate and easy to understand information on a subject that often raises unjustified alarmism.

Terna benchmarks the sites of other grid operators in order to evaluate the type and quality of information given. Subsequently, in collaboration with Fondazione Ugo Bordoni (FUB), the institute of high culture and research in Italy that boasts the best experience and expertise on the subject, the company created a work group to create a dedicated site.

The result is a site that combines scientific accuracy with direct and straightforward language on electromagnetic fields.

The site has 5 sections:

  • electromagnetic fields, with general information;
  • 10 Things to Know, a series of answers to frequently asked questions about EMFs, in particular concerning the effects they may have on health, the legislation in force, and what happens in the proximity of a power line;
  • electricity grids and electromagnetism, with definitions, graphics and pictures which clarify the characteristics of the electric and magnetic fields generated by power lines;
  • true or false, a quiz to test one’s knowledge;
  • more in-depth, with links to the sites of the World Health Organization and other institutions of reference, including the Bordoni Foundation.

 

Measures adopted in the planning stage

Terna can reduce the impact of its electricity lines on the landscape by identifying routes in areas with good landscape compatibility and choosing towers that blend in well with the environment. In the last few years, Terna has increased the alternatives at its disposal, among other things by having internationally famous architects design new towers.

Similar considerations hold for the construction of power stations. Stations have a much greater, albeit more limited, impact. In some cases, Terna plans to plant masking trees.

 

Mitigation

With regard to existing plants, mitigation measures aim at reducing their visibility and/or improve their integration in the surrounding area. In particular, Terna devises masking systems for station fences, upgrades the buildings, and uses naturalistic engineering techniques. (For further examples, see the “Management of impacts on biodiversity” section.)

These solutions also represent the basis for developing criteria for the design of new plants.

 

EU13Construction-site management

 For the management of construction sites, Terna has equipped itself with Operating Instructions – “Management of environmental aspects during plant construction” – to ensure compliance with the environmental policy adopted by the Company. It provides in particular for the construction site and the new service roads to be located in areas of lesser vegetative value (agricultural areas) whenever this is compatible with the technical requirements of the plan.

However, if the areas regard natural or semi-natural habitats, after the work has been completed, the area concerned must be environmentally restored to a condition that is as close as possible to what it was previously. Scheduling the stages of construction must take into account the vital needs of the species that are potentially affected and avoid the activities with the greatest impact during the periods when the species reproduce.

Furthermore, particular care must be taken in managing the waste produced on the construction site in compliance with the relevant regulations in force, such as avoiding spills and the temporary storage of polluting substances.

 

Contract work

The Operating Instructions “Management of environmental aspects during plant construction” provide instructions for minimizing environmental impact along the supply chain.

The obligations regarding the environment that apply to contract work entrusted to other companies were established according to the provisions of the applicable environmental laws and prescriptions of the ISO14001 standard and include aspects such as: preventive measures against contamination of groundwater, the limitation of damage to vegetation, the management of accidents, minimization of air emissions and noise, vehicle use, and the correct management of waste and excavated land.

 

The “Energy Bridge” between Sicily and Calabria: the Sorgente-Rizziconi power line

ponte_0.jpgIn June 2011, Luigi Roth, Chairman, and Flavio Cattaneo, CEO, in the presence of Stefania Prestigiacomo, Minister of Environment, presented the project and the works underway for the new 380 kV power line, the “Energy Bridge”, which is being built between the Sorgente (Messina) power station and the Rizziconi (Reggio Calabria) station, and which will be completed by the end of 2013.

The work will join Sicily and Calabria through the world’s longest 380 kV alternating current connection - a 105 kilometer long connection, 38 kilometers of which consist of a submarine cable. The power line will improve the quality and safety of the Sicilian electricity grid, which is obsolete and poorly connected with the rest of Italy. Once finished, the work will yield numerous benefits, also in terms of the environment: while 82 kilometers of new lines will be built in the provinces of Messina and Reggio Calabria, 67 kilometers will be buried and 170 kilometers of existing overhead lines will be demolished.

 

Safety and economic benefits

The work will allow for an overall savings for companies and families of nearly 800 million euro a year, thanks to the annulment of the price differential of energy in Sicily, which is currently 40% higher than the rest of Italy. The difference is due to an energy generation capability on the island that is less efficient than the rest of Italy, resulting in less competition. The construction of the power line, which will improve the connection between Sicily and Calabria, will allow for a greater use of energy flow produced by more efficient production plants in the south of Italy, thereby increasing competition which will result in a decrease in energy prices.

The work will also reduce the risk of blackouts in Sicily and will increase the safety, efficiency and quality of the electricity service in the entire area.

Environmental benefits

The “Sorgente-Rizziconi” connection will allow the removal of more than 170 kilometers of obsolete overhead lines (87 in Sicily and 85 in Calabria), significantly reducing the impact of electricity infrastructures on the territory involved.

The overhead part of the new connection, characterized by lines with a record single span of 1.3 kilometers in Scilla, uses huge single pole pylons - high tech innovative tubular supports built, for the first time in Europe, with mechanical characteristics that make them particularly suitable for installation in inaccessible areas. For example, a 20-kilometer long overhead connection from the station in Villafranca to the station in Sorgente will be entirely built using a total of 45 new supports.

Due to their compactness, which reduces visual impact and has a minimal encumbrance on the ground, which is 25 times lower than that of the traditional truncated pyramid pylons – 5/6 sqm versus 150 sqm – the tubular supports are a valid alternative to traditional pylons.

The submarine part of the work, on the other hand, which runs 38 kilometers under the Strait of Messina, will be constructed by laying cables in a single phase and reaching over 370 meters in depth in the Tyrrhenian Sea.

Moreover, in order to safeguard the territory, care was taken by Terna to avoid crossing the “Dorsale Peloritana” (Peloritana main line), in the province of Messina, and, in particular, the Site of Community Importance, “Antennamare-Curcuraci”, with an overhead line; the existing energy corridor (on the Sicilian side) will be used, so as not to occupy non-infrastructured areas. Furthermore, attentive environmental monitoring will be carried out on the construction sites through periodic inspections on the status of water, vegetation and fauna.