Other indirect CO2 emissions



In addition to the emissions corresponding to the consumption of electricity, other indirect emissions caused by Terna’s activities are connected with:

  • grid losses;
  • flights taken by employees.


Grid losses 2012

Grid lossesare defined as the difference between energy input by producers and imports and final consumption; significant losses for Terna are those associated with the transmission grid. The figure presented in the table below is based - for the first time - on the direct measurement of energy put into and taken out of the transmission grid (approximately 7,500 measurers), to which corrective technical coefficients are then applied in cases in which the point of measurement does not coincide with the boundaries of the transmission grid. It must be stressed that the responsibility for measuring the energy put into the NTG is Terna's, while for the energy taken out Terna may, on the basis of specific agreements, remotely read the measurements, which however remain the responsibility of the distributor companies. This entails a margin of uncertainty on the correctness of the measurements of electricity taken out, which has been reduced over the years thanks to cross-checks and the gradual resolution of discrepancies with distributors' data. For these reasons, starting from 2012, it was decided to use the arithmetic mobile mean of losses with a three-year window (the three years 2010-2012 for the year 2012) as the annual figure: in this way the margin of uncertainty and the risk of interpreting the effect of measurement errors as real trends are reduced.


% proportion with respect to energy demand GWh
EHV and HV grid 1.4 4,485

In previous publications the values presented were the result of a division of the losses of the electricity system (also including distribution grids) proportionally to the voltage levels, starting from calculations made assuming particular grid configurations and considering losses on lines owing to the corona effect, directly proportional to the voltage, and owing to the joule effect, directly proportional to the current, and losses on transformers. These values differed significantly from what emerged from the data based on measurements presented in the table, resulting in 8,710 GWh for 2011 and 8,663 GWh for 2010. Because of this, it was decided to not compare the 2012 data with the historical series produced up to now.

It is, anyway, necessary to specify that Terna can only contribute to determining the amount of losses, which are not completely under its control. To explain this point it is useful to distinguish between dispatching operations and grid development activities.

Dispatching operations are necessary to guarantee a constant balance between deliveries and withdrawals and avoid the onset of grid security problems and poor service. These operations are carried out, according to regulated criteria, in the context of production structures determined by the energy market, and therefore cannot be influenced by Terna with the aim of minimizing losses. It should also be noted that the energy market implicitly favours more efficient production and therefore entails a trend to reduce emissions of a much greater amount than that of grid losses.

With the same production structures, grid development activities would determine greater efficiency and therefore a reduction of losses. However, grid development enables the creation of production structures which were previously not possible and also enables the growth of consumption. Moreover, grid development itself is in part dictated by the need to connect new plants, the location of which is not decided by Terna. The overall effect on losses of grid development work cannot therefore be predetermined and is not even under the control of the transmission operator: other factors may more than offset the increased efficiency deriving from grid development. This applies both in terms of the absolute amount of losses, and in terms of the proportion of losses to total energy consumed.

Considering the production mix of the Italian generation system the CO2 emissions associated with grid losses amounted to 1,771,477 tonnes for the year 2012.

Flights by employees

Emissions corresponding to flights taken by employees show slight fluctuations over the three years. In particular this year they were down 3% compared with 2011, the year during which intensification of activities in the Balkans and the Mediterranean had led to an increase in air miles and emissions associated with international travel. 


Miles CO2 emissions (tonnes)
Kind of flight 2012 2011 2010 2012 2011 2010
Domestic 3,171,164 3,174,881 3,065,573 1,046 1,048 1,010
International 1,365,577 1,523,415 1,128,909 329 367 271
Intercontinental 475,926 521,433 945,914 99 109 195
Total 5,012,667 5,219,729 5,140,397 1,475 1,523 1,477