Direct and indirect CO2 emissions


Greenhouse-gas emissions connected with Terna’s activities are caused by:

  • direct consumption of energy sources (petrol and diesel for vehicles, diesel for generators, oil for heating, natural gas for heating);
  • indirect consumption of energy sources (electricity consumption);
  • leaks of SF6 (sulphur hexafluoride), a greenhouse gas used in station equipment for its high insulating power;
  • leaks causing consumption of R22 coolant gas, used in air conditioning systems.

SF6 leaks are the main direct source of greenhouse-gas emissions by Terna; in particular in 2012 they account for 90% of total direct emissions. From 2010 to 2012 the quantity of SF6 present in Terna's plants increased by 104 tonnes (+29%). This is a trend – common to many transmission operators – destined to continue in the next few years for technical reasons associated with the higher insulating performance of the gas and to the smaller size of stations built with equipment containing SF6, compared with more traditional solutions. For this reason the indicator Terna looks at is the percentage of leaks compared with the total gas present in the equipment. Over the three years the percentage figure for leaks declined gradually and in 2012 was 0.59%. The programmes to limit the proportion of SF6 leaks are illustrated in the specific paragraph.


2012 2011 2010
Direct emissions
SF6 leaks 62,791 57,406 60,313
R22 leaks  110 25 240
Petrol for vehicles 28 520 493
Diesel for vehicles 5,741 5,605 5,520
Natural gas for heating 518 531 408
Oil for heating and for generators 818 836 954
Total direct emissions  70,007 64,922 67,928
Indirect emissions
Electricity 70,008 71,463 70,692
(1) Direct consumption is converted into CO2 equivalent emissions using the parameters indicated by the Greenhouse Gas (GHG) Protocol Initiative. Indirect consumption of electricity is converted taking into account the proportion of thermoelectric production to total Italian electricity production for 2012. The reference for the division of the production mix is the “Monthly Report on the Electricity System” with the results for December 2012, available on the website