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  • Grid development and system emissions
  • Reducing emissions: Terna’s plans

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.

In terms of emission reduction, Terna’s plans can be grouped into four different types:

Limiting SF6 leakage

In the four-year period 2009-2012, Terna implemented a campaign to install new, more leak-proof equipment, with an estimated reduction in the leakage rate regarding total equipment installed - after exceptional faults - of approximately 0.10% over the five years after the installation campaign. Based on this estimate, the leakage rate was expected to be around 0.60%, given that the average rate for the period 2007-2008 was 0.70%, after exceptional faults.
The leakage rate, which is the most significant indicator of the reduction measures adopted, actually decreased after 2012 and in 2017 stood at 0.47%. The rate, whilst up on the previous year (2016: 0.39%) is in line with the average over the last five years and above the target.

Company fleet

The Company's operational vehicles are used nationwide to carry out power line inspections and, in general, to visit infrastructure and construction sites.
Terna's vehicle fleet consists of:

  • four helicopters, purchased in 2015, for carrying out scheduled and random inspections of power lines;
  • a fleet of cars that was renewed in 2017, of which 92% are equipped with Euro 6 and Euro 5 engines.

Quantities and emissions for motor vehicles(1)

Total motor vehicles no. 1,344 1,323 1,514
Nitrogen oxide (NOx) emissions(2) kg 7,631 8,260 8,980

(1)The table shows the vehicles in Terna’s fleet that, in the period in question, were refuelled on at least one occasion, based on claims for fuel expenses. Consumption data for fleet vehicles is shown in the following tables.
(2)The figure is calculated on the basis of the data provided by motor manufacturers and included in registration certificates, as well as on estimates of the mileage covered by the vehicles. The figure shown in the table for 2017 refers to 85.3% of the Company’s operating vehicles (85.4% in 2016 and 68.2% in 2015).

Energy Management System

In line with its energy efficiency objectives, since 2015 the Terna Group has been certified in accordance with the UNI CEI EN ISO 50001:2011 standard and is committed to constantly improving its Energy Management System. In 2017, sensors were installed at 80% of Terna's main sites to measure energy consumption in real time. The analysis, which was carried out using time bands and the entire calendar year, has highlighted numerous peculiarities regarding electricity use and will enable improvement targets for all the sites monitored to be defined in 2018.
In 2017, a pilot project regarding the online monitoring of the electricity consumed by transformer substations was also launched, and in 2018 a representative sample of substations, broken down by type of activity, will be involved nationwide. More than 20 meters will be installed in each station to accurately monitor the electrical energy used.

Energy efficiency in substations and offices

At Terna, the development of energy efficiency programmes relating to the use of electricity in substations and offices is experimental, as the Company's electricity consumption falls within the category of "own transmission uses" which, according to the industry’s regulator, are not to be included in operating costs.

Reduction of CO2 emissions in the electricity system
Improving the efficiency of air conditioning systems During 2017, Terna implemented four projects to improve the efficiency of air conditioning systems at the Infrastructure Units in Suvereto (GR), Bologna, Florence and the Rome Operating Area, which will lead to a reduction of approximately 63 tonnes in annual CO2 emissions.
Improving the efficiency of lighting systems In 2017, Terna implemented two projects to improve the efficiency of lighting systems at the Suvereto (GR) and Central and Southern Lazio (RM) Infrastructure Units, which will reduce annual CO2 emissions by around 167 tonnes.
Summary of previous years' initiatives Since 2014, three energy efficiency initiatives have been launched, leading to a reduction of around 270 tonnes of CO2 at 31 December 2017 (equal to 75 tonnes of CO2 in 2017).
Forecast for initiatives in 2018 For 2018, six energy efficiency initiatives have been planned with an estimated annual reduction of 60 tonnes of CO2.
Self-production of electricity from renewable sources In 2017, Terna implemented two projects regarding the self-production of electricity from renewables for the Turin Botticelli office and the Camin (PD) Infrastructure Unit, which will result in a reduction in annual CO2 emissions.

The overall picture of all Terna's environmental data is available for download here.