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

CO2 emissions: comparative data

Comparison of Terna with other companies as regards the emission of greenhouse gases was done by using total direct and indirect emissions in CO2 equivalent thousands of tonnes as a reference.

Both the figures of the transmission companies (TSO panel), the bigger listed Italian companies (FTSE-MIB) and the international sustainability leaders (SM-Supersector Leaders) were taken into consideration.

The emissions in absolute terms do not reflect the various companies' performance in the efficient use of energy and in limiting climate change emissions, which should be assessed over time and with reference to normalisation factors which eliminate the differences deriving from the varying nature of business and the size of the company.

In the absence of significant normalisation factors valid for all sectors, it was deemed in any case of interest to present the company data on CO2 emissions in absolute terms - despite the limited comparability. Such figures, which vary greatly in terms of magnitude from one case to another, at least provide an indication of the size of greenhouse gas emissions - and therefore of the practical need to contain them from the point of view of sustainability, in the various sectors and various companies.

For example, of the TSOs, the highest figure, (in line with the analysis of the 2010 data) is for Eskom which operates in South Africa and includes electricity generation among its many activities, while the lowest is for ISA, a TSO which operates in Latin America and does not deal with electricity production or distribution.

For 2012, the emission of greenhouse gases related to Terna' activities was 140.0 CO2 equivalent thousand tons; in 2011, the year for which comparative figures are available, the emissions were 136.4 CO2 equivalent thousand tons.

TSO Panel: 17 figures available; average CO2 emissions: 26,121.9 thousand tonnes CO2; minimum value: 3.5 (ISA – Latin America); maximum value: 231,900 (Eskom - South Africa). In this comparison Terna comes out below the average, which is the highest of the averages of the three panels and influenced by values registered by transmission operators who also own electricity generation businesses.

FTSE-MIB Panel: 23 figures available(1); average emissions of CO2: 9,472.7 thousand tonnes CO2; minimum value: 12.3 (Ubi Banca); maximum value: 123,832.0 (Enel) Terna is one of the big Italian companies with lower emissions, well below average and with total emissions only just higher than those of banks and insurance companies, the category with the lowest values.

RobecoSAM Panel - Supersector Leaders: 19 figures available; average CO2 emissions: 5,997.2 thousand tonnes CO2; minimum value: 10.1 (Telenet Media); maximum value: 51,810.0 (Repsol – Oil and Gas). In this comparison too, Terna confirms a quantity of emissions well below average. The extreme variability of the company figures makes a graphic representation of little significance; the table shows the minimum, average and maximum values in the three panels considered.

Greenhouse gas emissions - thousands of tonnes  CO2 - 2011
  TSO FTSE-MIB RobecoSAM - Supersector Leaders
Average 26,121.9 9,472.7 5,997.2
Max 231,900.0 123,832.0 51,810.0
Min 3.5 12.3 10.1
Standard deviation 62,294.2 27,556.6 14,484.9
Terna 136.4
(1) In the case of the indicator of CO2 emissions, for two of the companies on the FTSE MIB panel the figure published in the document “CDP Italy 100 Climate Change report 2012” as part of the Carbon Disclosure Project, was considered.