Air protection GRI - G4: EN21

The use of natural gas as its principal energy source enables the Company to minimise emissions of sulphur oxides and particulate matter.

Nitrogen oxide (NOx) emissions, the only significant polluting emissions, arise from the combustion of natural gas in the gas turbines installed in the compression stations (compression and storage). To reduce these emissions, a programme was established several years ago to modify the existing turbines and install new units with low emission combustion (DLE) systems.

In 2015, the DLE turbocompressors were put into service at the Enna (TC3) and Cortemaggiore (TC1) plants.

Total emission NOx (t)

Total emissions of nitrogen oxides in 2015 were 433 tonnes (-12.9% compared with 2014). This decrease was due to the increasingly extensive use of low emission DLE turbines, which accounted for 88% of hours of operation for transportation and 89% for gas storage.

This reduction is even more impressive if we consider that the fuel gas used for the operation of gas turbines, which is responsible for the most significant portion of emissions, rose for transportation (+4.6%) as well as gas storage (+15.3%).

NOx emissions into the atmosphere are determined based on direct measurements or, if these are not available, on emission factors present in the relevant literature (the EMEP/EEA Air Pollutant Emission Inventory Guidebook of the European Environment Agency).

The table shows all the objectives pre-set in 2010 through key performance indicators (KPI) with targets in 2015 that aimed to reduce emissions of nitrogen oxides. The targets of three of the four KPIs were achieved one year early.