The building of new electricity lines and stations provided by the 2015 Development Plan will produce positive effects in terms of emission reduction by the electricity system.
Given the time horizon of the 2018 Development Plan, the emissions of CO2 might decrease by about 16 million tons/year.
The effects can be grouped into three categories:
Reduction of grid losses
Grid losses depend, among other things, on the length of the section of the transmission grid over which the electricity has to travel.
In the simplest possible terms, the further away the point of consumption (withdrawal from the NTG) is from the point of production (injection into the NTG), the greater
the losses for the same amount of consumption. In addition, over an equal distance, the losses are greater on a lower voltage line. Development works that improve the grid
bring the points of withdrawal and consumption closer together: if all else is equal, grid losses are consequently reduced. A similar result is achieved by upgrading a section
of the grid, for example, when a 400 kV line replaces a 150 kV line along the same route. The entry into service of the main development works provided for in the 2018
Development Plan will lead to an estimated reduction in energy losses through the grid of approximately 1,600 GWh a year. If such a loss reduction were to equate
to a decrease in production from fossil fuel sources, this would amount to a reduction in CO2 emissions of approximately 90,000 tonnes per year.
Improvement of the production mix and interconnection with other countries
One of the main purposes of developing the electricity transmission grid is to overcome the transport limits between “electricity zones”.
The existence of these limits imposes a number of restrictions on the possibility of production by more efficient generation units, namely units which pollute less in terms of CO2 emissions,
and at the same time makes production by obsolete substations necessary for grid security.
The work envisaged in the Development Plan, together with the expansion of interconnection with other countries,
would enable a more efficient production mix, with a larger proportion of production by plants with higher yields. The same final consumption
quantity would thus be fulfilled with a smaller quantity of fuel: the benefits are quantifiable as a reduction in CO2 emissions of up to 8,530,000 tonnes a year.
Connection of plants using renewable energy
The main contribution to the reduction of CO2 emissions derives from the connection of renewable energy plants, which is among the initiatives
considered in the 2018 Development Plan. Production of energy from renewable sources has grown rapidly in potential in recent years. In particular, wind and photovoltaic
generation plants have witnessed a considerable increase, especially in Italy's southern and island regions.
One of Terna's main tasks is to plan upgrades of the NTG in order to promote the production of electricity from renewable sources,
seeking to overcome any grid and operational constraints that may affect the injection of such energy into the grid, which benefits from priority dispatching rights.
The development solutions planned in response to these critical issues include interventions to upgrade sections of the primary grid,
which indirectly reduces the limits on production from non-programmable renewable sources (NPRS), and interventions designed to upgrade
local sub-transmission grids into which the energy produced from NPRS is directly injected. In addition to these interventions, collection
stations have been planned for NPRS on the primary 400 kV grid, which will limit the number of new 150 kV power lines to be built with respect
to the number that would otherwise be required. Overall, the works envisaged in Terna's 2018 Development Plan will release power from renewable
resources amounting to approximately 5,500 MW, thereby obtaining a reduction in CO2 emissions of approximately 7,080,000 tonnes a year.
The overall picture of all Terna's environmental data is available for download here.