Measures taken during the planning and design phase

Terna can reduce the impact of the power lines on the landscape, by identifying routes in areas with a good landscape compatibility and by choosing pylons that blend well in the territory. For this reason Terna is developing coordination activity with territorial stakeholders from the very first phases of planning and designing the new lines.

In the last few years, Terna has also resorted to planning new pylons by internationally renowned architects.

Similar considerations apply for the construction of power stations, that have a much greater, even if more limited, impact: in some cases,  tree planting is used to camouflage the power stations.

 

Grid measures

These involve 3 different type:

• Grid upgrading;
• Cable burying;
• Grid improvement.

Grid Upgrading  is a complex measure that involves different grid elements at the same time: often, when building new lines, some sections of the grid are removed.

Upgrading measures are mainly implemented by:

• Replacing some plants with others having higher characteristics. A typical example is represented by the introduction of new 380 kV connections replacing a greater number of lower voltage electricity lines. It is sufficient to think of the new 380 kV Paternò-Pantano-Priolo power line, that will extend for 63 kilometers between the provinces of Catania and Syracuse;
• Eliminating grid portions that are of little or no use after the new building activity which has strengthened the grid;
• Avoiding facility upgrading, mainly power lines, that have reached saturation, through the  addition of new grid elements, such as stations.

The construction of a new plant can cause the effect of reduced territory occupation, through the removal of old power lines.  Especially near cities, upgrading measures help solve problems linked to the presence of electricity infrastructures in areas with progressive urbanization. In  all of the upgrading activity provided for by the Development Plan, demolitions greatly exceed new constructions, with the positive effect of  freeing the territory from electricity lines.

Cable burying is often required by local authorities as the first option for the building of new lines: this is because it eliminates or reduces the negative impact on the landscape caused by overhead lines.  
Actually, this type of measures presents various technical and economic problems. With respect to overhead power lines, buried lines:

• Are less reliable in the long run;
• Involve longer times for  repair in case of malfunction;
• Involve a more significant building activity in building sites compared to overhead lines;
• Involve significantly higher implementation costs (from 5 to 10 times higher)

At the end of 2010, there were about 1250 km of buried lines.

Improvements refer  to the conversion of existing power lines to a higher voltage, through the building of new conductors and pylons. This measure can lead to a replacement of the old pylons with larger ones that take up more space: this happens, for example, when a 130 kV power line is improved to 220 kV. Compared to building a new line, this type of measure has the advantage of generally using the existing infrastructure corridors, thus avoiding the occupation of new parts of land.

 

Mitigation measures

In the case of existing plants, mitigation measures aim at reducing the visibility and/or improving the integration of their structures in the territory.
In particular Terna:

 

• Builds masking systems as fences;
• Upgrades the buildings;
• Uses naturalistic engineering techniques.

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