Initiatives to reduce own emissions

EN18With regard to the reduction of greenhouse-gas emissions, Terna concentrates on several voluntary programs concerning its main sources of such emissions:

  • a program for containing the incidence of SF6 leakage: Terna has implemented a number of initiatives, such as the early detection of leakage through on-line monitoring systems and the search for technological solutions to increase the air-tightness of the equipment and of components;
  • feasibility studies for initiatives on energy conservation in power stations;
  • a program for reducing the consumption per km of the corporate vehicle fleet, which entails a reduction of CO2 emissions per km (g/km);
  • a program dedicated to the energy efficiency of the buildings (corporate offices).

The first two cases are initiatives that can have a significant quantitative effect, but only in the medium-to-long term. The results of the third program are already tangible, but regard a source of emissions that is less significant from the quantitative point of view.

Reduction of SF6 leakage

Thanks to its physical and chemical properties, which make it an excellent insulator, SF6 (sulfur hexachloride) is used as an insulator in some kinds of electrical equipment, such as switches, current transformers and armored systems. The latter allow building power stations in smaller areas and with less maintenance needs. Because of these properties, it is foreseen that equipment with SF6 will be increasingly used, as it is by other transmission companies abroad.

Part of the gas present in infrastructure is dispersed in the air because of the defective tightness of gaskets, during failures and sometimes also during pressure restoration. SF6 is classified as a greenhouse gas. Terna therefore intends to keep SF6 leakage under control to contain and, if possible, reduce its incidence with respect to the total quantity of the gas used. If the quantity of dispersed gas could be larger, because of the increased use of equipment insulated with SF6, a reduction in the incidence of leakage would have a significant impact in terms of emissions avoided.

Although the way in which SF6 leakage was handled as an indicator of its own performance with reference to climate change, identifying a target is still being examined carefully. In fact, there are several elements of uncertainty:

  • a rise in awareness and attention to the subject is reflected in improved measurements of leakage, resulting in – for the years in which the containment activities were started (2009-2010) – what apparently seems to be deteriorating performance;
  • the occurrence of breakdowns resulting in the significant leakage of gas – the probability of which increases given the growing use of SF6 gas in the equipment of large stations – can considerably alter the trend;
  • if, on the one hand, the installation of equipment with better withstanding performance tends to reduce the incidence of leakage, on the other, the obsolescence of equipment already installed could cause an increase in leakage;
  • Terna already registers low values of SF6 leakage in comparison to other TSOs (see the dedicated box in this paragraph), therefore, further reductions, which have growing marginal costs, can only be contained, with a high probability of being counterbalanced by adverse factors, already mentioned, of potentially greater impact.

Net of exceptional breakdowns, and possible effects of obsolescence of equipment in operation, it is estimated that the installation of new devices with greater withstanding (such as increased reliability transformers), begun in 2009 and continued in 2010 and 2011, may bring about an estimated reduction of 0.1% in the incidence of leakage over the five year period starting from the start of the installation campaign, without prejudice to the effective availability of the new equipment. Based on this estimate, and always net of the factors mentioned, it is expected that by 2014 the incidence of leakage may converge on values varying around 0.6%, considering that the average incidence for the period 2005-2009 was 0.7%.

 SF6 LEAKAGEsenza-titolo-1_2.jpg

(*) Losses net of an exceptional event (1.07% event included).

In 2011, the incidence of leakage was 0.60%, down from the previous two years (2010: 0.73%; 2009: 0.89%). As illustrated up to this point, from the information available it is not possible to interpret the results as a convergence towards the objective. 

In 2011, the application of the registration procedure of SF6 gas top ups has successfully continued aiming at identifying equipment with anomalous leakage and assess the feasibility of a program of targeted maintenance. The study results will enable the Company to establish a more precise target value for the incidence of SF6 leakage.

Programs and initiatives for SF6 gas management existing since 2008 are reported below:

  • procedure for monitoring leakage and reduction of dispersion of the gas during pressure restoration: the procedure for reading requires the registration of the gas used and dispersed for every single station (up to 2007, measurement of the leakage was provided by the overall quantities of SF6 acquired, net of new plants);
  • multi-function compact modules (set of different kinds of equipment) with a reduction of at least 30% of the SF6 necessary for insulation with respect to other equipment. After the positive trial results, the equipment is considered an applicative standard and will be installed as necessary;
  • detection systems with remote transmission of leakage of the gas in equipment: after having completed the installation of the Lacchiarella power station, assessment of results for a possible widespread application is under way. The early detection by the remote-maintenance center of the equipment where the pressure of the gas is falling anomalously allows the Company to do targeted work on the equipment, thus also avoiding plant downtime because of insulator leakage;
  • new highly reliable (TA) measurement transformers sealed, with maximum leakage of 0.1% a year: since 2010, the plan for replacing old equipment with new transformers is under way.


Energy saving in stations

Electricity is used in power stations to enable the equipment and its remote control to function.

The main sources of consumption are:

  • cooling power transformers;
  • external lighting;
  • air-conditioning and heating systems in technical locations;
  • auxiliary command, control, and protection circuits of all equipment and machinery.

Although the energy consumed is only the quantity that is strictly necessary to ensure the operation, research of opportunities to save is sought for through:

  • natural or automatic circulation systems that optimize the functioning of cooling pumps and fans in transformers;
  • the installation on station buildings of photovoltaic panels that at least cover the consumption of the computers that manage the plants.

The measurement of the effects of the initiatives described will be possible only in the medium term, when the projects have reached a more advanced stage.


SF6 leakage: comparative data

The comparison between Terna and other operators concerning SF6 leakage is made by taking as the reference point the incidence, i.e. the percentage of leakage with respect to the total gas used. 

Since the use of SF6 gas is unique to grid operators, only the data of the companies belonging to the TSO panel were taken into consideration. 

In 2011, the average incidence of SF6 leakage for Terna was 0.6%; in 2010, the year for which comparison data is available, the incidence percentage was 0.7%.

When compared to other grid operators, Terna indicates a incidence of SF6 leakage lower than average, confirming the results reported in last year’s Sustainability Report. 

TSO Panel: 11 items of data available; average incidence of SF6 leakage: 1.1%; lowest figure: 0.3%; highest figure: 2.3%; standard deviation: 0.7%.Terna ranks well below the average for the incidence of leakage.

By comparing data with those belonging to 2009, which were published last year, for 7 out of 8 available data, no significant changes in incidence were recorded, which increases or decreases by 1-2 decimals. 



(*) The incidence of leakage was calculated as a percentage of loss on the total gas installed in the equipment.


Reduction of emissions connected with energy consumption in officesEN5

Since 2011, “Criteria for Energy Efficiency in Terna’s Buildings” guidelines have been operational. These guidelines establish a common standard for constructing buildings with the lowest energy impact, and provide integrated criteria for the planning/upgrading of buildings. The aim of the document is to save energy over time, thereby reducing direct greenhouse gas emissions. For 2012, an information campaign and relative dissemination is scheduled, also for activities linked to the energy management system.

In offices the main sources of energy consumption are connected with lighting, heating and air-conditioning, and the use of computers and printers.

In 2011, the Company measured the reduction of consumption obtained by the replacement of 156 personal computers models (only desktop). The new desktop models allow for an average saving of energy consumption equal to 80%.


Reduction of emissions connected with mobilityEN29

 The Company’s vehicle fleet – which is used mainly for inspecting and repairing lines – is not concentrated in only a few locations, but is used over a widespread area. Therefore, there is no problem of impact on specific areas, but a general pollution effect. The most important measure for reducing the impact of transportation on the environment consists in a renewing the fleet every 48 months, carefully indicating technical specifications during the purchasing of the vehicles (devoting attention to the environmental impact) and  carrying out scrupulous maintenance

  2011 2010 2009
9 9 9
Euro 5138 97 79
Euro 4 985 1.009 1.033
Euro 3 (or lower)  219 273 346
Total vehicles
1.351 1.388 1.467
(1) The table shows the vehicles in Terna’s fleet by December 31, that during the period in question refueled at least once as recorded in the fuel documents. Only operating vehicles are considered excluding managerial vehicles.

During 2011, Terna has confirmed the actions undertaken to reduce the impact of employee mobility on the environment consisting of:

  • optimization of its offices localization in large towns (already carried out for Rome and Milan and planned for Florence);
  • monitoring of employee travel;
  • introduction of the use of equipment for videoconferences which can be connected with the equipment of suppliers, partners, and other Terna’s offices;
  • incentives for the use of public transportation through:
  1. easy terms for employees in purchasing annual passes (agreements have been signed with the public transportation companies of Rome and Milan, with 167 employees in Rome and 63 in Milan having purchased passes in this way);
  2. creation of services connecting two offices in Rome and one in Milan with the closest public transportation junctions at no charge to employees;
  • courses on off-road vehicles regarding safety and emission reduction.


Terna uses operating vehicles daily to inspect lines and reach operating plants located throughout Italy. Such inspections often require the use of 4WD vehicles, since pylons can only be reached through unpaved trails.

Since July 2008, the Company has participated in Quattroruote’s “10X10” project. So far, 35 companies participating in the project are committed to reducing the CO2 emissions of their vehicle fleets. In joining the project, Terna confirmed its concern for reducing the impact caused by emissions deriving from its corporate mobility, and ultimately the fuel consumption and efficiency of its corporate fleet.

In November 2011, a campaign was launched to replace the remaining Euro class 3 and Euro class 4 vehicles, which should be completed in 2012.  

The change in the vehicle classes – compared to what is provided for in the table – and the renewal of the vehicles will lead to improving the fleet’s efficiency, with a reduction in consumption and emissions. 

The replacement campaign, which involves nearly 80% of the fleet’s vehicles, envisages, with respect to CO2 emissions of vehicles used for business transportation, a compensation plan through the creation and protection of new green areas in Rome, Parco della Madonnetta, Madagascar and Costa Rica.

Reaching this objective is ensured through the collaboration between Terna, the vehicle suppliers and LifeGate’s Zero Impact project.

Thanks to the creation and preservation of these wooded areas, in the next four years the carbon-dioxide emissions – quantified as more than 10,222,763 kg – generated by Terna’s 840 operating fleet vehicles, will be offset.

Emissions were estimated on the average carbon dioxide per vehicle (from data supplied by the manufacturer) per kilometer driven and on the estimated number of kilometers covered each year by Terna’s fleet.

The areas involved cover 14,000 sq m in Rome, 510,756 sq m in Madagascar and 2,019,848 sq m in Costa Rica.

Reforestation will compensate over 42% of the Terna fleet’s annual CO2 emissions.