Other emissions of CO2

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

  • employee flying
  • grid losses.

The emissions corresponding to employee flying recorded a decrease of 6.4% in 2010 with respect to 2009, mainly because of fewer intercontinental flights following the sale of the Company’s Brazilian subsidiary at the end of 2009.  


CO2 emissions (tons)
Kind of flight 2010 2009 2008 2010 2009 2008
Domestic 3,065,573 3,511,970 3,793,592 1,010 1,013 1,09
International 1,128,909 1,223,462 1,306,497 271 260 269
Intercontinenetal 945,914 1,618,459 1,152,414 195 306 231
TOTAL 5,140,396 6,353,891 6,252,503 1,477 1,578 1,589
Grid losses are defined as the difference between the energy injected by producers and imports and end consumption. The losses that are significant for Terna are those associated with the transmission grid, which in the past were calculated with regard only to lines with a voltage of not less than 220 kVi. Since 2009 – following the acquisition of about 18,500 km of Enel high-voltage lines, losses on HV lines have also been considered. Both measurements are the result of an estimate, which breaks down the total losses of the electric system (including the distribution networks) in proportion to the voltage levels, beginning with calculations performed assuming particular grid configurations and considering the losses on lines because of the corona effect directly proportional to the tension and because of the joule effect directly proportional to the current, as well as losses in the transformers. 


  % with respect to energy demand GWh
  2010 (1) 2009 2008 (2) 2010 2009 2008 (2)
EHV grid 1.25 1.27 1.32 4,077 4,067 4,457
HV grid 1.42 1.44 na 4,632 4,612 na

(1) Calculated on the basis of the “Provisional operating data of the national electric system 2010”.   
(2) The 2008 values were calculated only for the Italian assets.

It should be noted that Terna can only contribute to determining the extent of the losses, which are not completely under its control. To explain this fact, it is useful to distinguish between dispatching activities and activities for developing the grid.  
Dispatchingi is necessary to ensure the constant balance between injections and withdrawals and to avoid problems of grid security and poor service. These activities take place according to regulated criteria within the framework of production set-up determined by the energy market and therefore cannot be conditioned by Terna and the objective of minimizing losses. On the other hand, it should be noted that the energy market implicitly favors the more efficient productions and thus entails a trend of emission reduction that is much greater than that of grid losses.

With equal production set-ups, the activities of grid development would determine greater efficiency and therefore a reduction of losses. However, the development of the grid leads to production set-ups that were not previously possible and also enables consumption to increase. Furthermore, grid development itself is partly dictated by the need to connect new plants, whose location is not determined by Terna. The overall effect of grid development on losses is therefore not predetermined and not even under the control of the grid operator. Other factors can more than offset the increase in efficiency ensuing from the development of the grid, in terms of both the absolute quantity of the losses and the losses as a percentage of the total energy consumed.       

The CO2 emissions associated with grid losses in 2010 were as follows:

  • for the EHV grid, 1,749,028 tons      
  • for the HV grid, 1,986,896 tons    

Terna is developing new specifications for the acquisition and use of medium-voltage/low-voltage transformers with “low losses of electricity”. The adoption of the new specifications is in keeping with the Electricity Authority’s resolution ARG/elt 348/07. The objective of the new specifications is the construction and acquisition of class-Ak transformers, the highest-performing, with a reduction of losses due to the load of 11% with respect to the current values. As far as “in vain” energy losses are concerned, the adoption of the B0 class will lead to an average loss reduction of 28% with respect to the current values. The reduction will also have an impact on grid losses.