The emissions

Direct and indirect emissions of CO2
Greenhouse-gas emissions connected with Terna’s activities are caused by:

  • direct consumption of energy sources (gasoline and gas oil for vehicles, gas oil for generating sets and heating, and methane for heating)
  • indirect consumption of energy sources (electricity consumption)
  • leaks of SF6 (sulfur hexafluoride), a greenhouse gas used in station equipment for its high insulating power.

Leakage of SF6 is the main direct source of Terna’s greenhouse-gas emissions.
From 2008 to 2010 the quantity of SF6 present in Terna’s plants increased by 43 tons (+13.6%). This trend is common to many transmission companies and is bound to continue in the near future because of technical reasons connected with the superior insulating performance of the gas and the reduced encumbrance of stations constructed with equipment containing SF6 with respect to more traditional solutions. For this reason, the indicator that Terna watches is the percentage of leakage compared to the total quantity of gas contained in the equipment. In 2010 leakage decreased by 12% in absolute value, entailing a reduction the incidence to 0.73%, compared to 0.89% in 2009. This contributed to the reduction of Terna’s direct emissions.

Tons of CO2 equivalent (1)

  2010 2009 2008(2)
Direct emission      
Gasoline for vehicles (3) 493 483            626
 Gas oil for vehicles (3) 5,520 5,368          5,462
 Gas oil for generating sets and heating 954 983            853
 Methane for heating 408 344            271
 Leakagei SF6       63,223     71,828        81,499
 Total direct emissions        70,597     79,007        88,710
Indirect emissions      
 Electricity 81,700 75,680        80,350
Total emissionis 152,297   154,687      169,061

(1) The conversion of direct consumption into emissions of CO2 equivalent is made using the parameters specified by the Greenhouse Gas Protocol (GHG) Initiative. For indirect consumption of electricity, the conversion is made taking into account the weight of thermoelectric production in total Italian electricity in 2010. The reference for the breakdown of the production mix is the “Monthly report on the electricity system” for December 2010, which is available online at The GWh produced by the photovoltaic plants sold to TerraFirma did not entail CO2 emissions.

(2) The 2008 values include the emissions of Ternai Partecipações. For Italy alone total direct emissions in 2008 amounted 87,890 tons of CO2 equivalent, while total indirect emissions amounted to 79,484 tons of CO2 equivalent.

(3) The emissions shown in the table regard the consumption the vehicles of Terna’s fleet that during the period in question refueled at least once according to the fuel documents. Only operating vehicles, and not managerial ones, are considered. The CO2 data for 2009 and 2008 were reclassified in light of the new boundary of data recording.