Energy distribution



Areti manages the electricity distribution network of Rome and Formello, extending over approximately 31,700 km and capable of supplying about 2.8 million residents. In terms of volumes of electricity distributed, about 9,200 GWh in 2021, Acea is the third largest Italian operator in the sector.

Table no. 51 presents the principal plant data of the Company, including the number of primary and secondary substations, the transformers134 and the km of overhead and underground distribution lines.

The environmental indicator related to the protection of the land, calculated as a percentage share of the underground high-voltage network (HV) in relation to the total of the HV lines in use (over- head and underground), improved and was 47% in 2021, also as a result of the continuing transformation and modernisation of the high and extra-high-voltage electricity distribution grid.

Table no. 51 – Number of overhead and underground distribution lines and plants (2019-2021)

systems and output
  u. m. 2019 2020 2021
High-Voltage/High-Voltage – High Voltage/Medium-Voltage primary substations n. 70 70 70
High-Voltage/High-Voltage and High-Voltage/Medium-Voltage transformers n. 170 171 170
transformation power MVA 7.781 7.881 7.921
substations in use n. 13.238 13.292 13.309
Medium Voltage/Medium Voltage - Medium Voltage/Low Voltage transformers n. 12.883 12.897 12.893
transformation power MVA 6.282 6.298 6.313
overhead and underground networks
high voltage network – overhead lines km 282 282 275
high voltage network – underground lines km 243 243 244
medium voltage network – overhead lines km 422 421 420
medium voltage network – underground lines km 10.470 10.211 10.269
low voltage network – overhead lines km 1.642 1.642 1.642
low voltage network – underground lines km 18.417 18.511 18.829


The plan to modernize the high-voltage electricity distribution grid (150 kV), defined in the Memorandum of Understanding signed in 2010 among Areti SpA, the Municipality of Rome and Terna SpA continues year on year, as noted above. The actions reduce the environmental impact, through demolition of lines and removal of pylons, as well as contributing to energy savings through works to reconfigure and optimise the HV grid:

  • works continued to dismantle decommissioned HV lines, with removal of a total of 48 pylons for 150-kV and 60-kV lines
  • 6 km of 150-kV underground lines with oil-filled cable were decommissioned on the Belsito - Tor di Quinto stretch, and an- other 3.6 km with the same specifications on the Belsito - M. Mario/Flaminia stretch
  • works continued for creation of the new Roma Nord - San Basil- io stretch of 150-kV underground line, with a length of 3.4 km
  • creation of the new stretch on the 150-kV Selvotta - Castel Romano overhead line has begun (5.8 km with 24 pylons)
  • New 150-kV HV XLPE cables have been commissioned on the stretches Belsito - Tor Di Quinto” (3.8 km) and Belsito - M. Mario/Flaminia, each with a length of 3.8 km.

The management of the electricity distribution network of Rome and Formello is characterized by the continuous improvement of the performance, with a particular focus on energy efficiency. Areti carries out works, including reclassification of medium-voltage lev- els from 8.4 kV to 20 kV and installation of MV/LV transformers with very low losses, which help to limit network losses. In 2021 losses of energy on the grid were approximately 6% of total issued power, in line with the previous year. For further information see the Energy savings section in the chapter The use of materials, energy and water.

Upgrading of electricity lines supports the energy transition. In this context, some projects launched by Areti, such as PlatOne and G.I.M.M.I., are particularly challenging. The first, which also in- volves Acea Energia, aims to optimise management of the increase expected in loads on the distribution grid, actively involving custom- ers. The second focuses on a system to improve grid monitoring and increasing the efficiency of maintenance. See the corresponding info. boxes for details.


The PlatOne (PLATform for Operation of distribution Networks) project is funded by the European Horizon 2020 project and involves ten public-private partnerships from Italy, Greece, Belgium and Germany, with coordination by the German Aachen University. Through the companies, Areti and Acea Energia, Acea heads the Italian pilot project on Rome, in three specific areas of the capital, working with ENEA, Siemens, RSE, ENG and Apio.

The project promotes an innovative approach to the management of distribution grids, aimed at increasing safety and stability. In the coming years, urban distribution grids will see a significant increase in loads, linked, among other factors, to the diffusion of electrical vehicles and heat pumps as well as an increase in distributed generation connected via medium and low voltage. Specifically, there could be consumption or generation peaks in certain periods of the year that are critical for the gird. Therefore, to optimally manage these it is possible to actively involve end users in grid operation, through creation of a “local flexibility market”. The PlatOne plat- form experiments with this solution, developing a multi-platform system capable of involving all market players.

For the end customer, the project implements and standardises a technological solution enabling the resource and certifying all energy transactions connected to flexibility using blockchain technology.

In addition, the user is provided with an app, for interaction with the aggregator, e.g. offering the possibility to modulate loads during certain time periods. The aggregator processes the flexibility supply of its customers and sends them to the market platform, where flexibility demand of the distributor is also received, connected to grid requirements. By linking supply and demand, and the possibility to actively involves customers in the management of infrastructure, a virtuous cycle is generated enabling the distributor to optimize flows and enabling customers to receive an economic benefit in exchange for the service they offer.

To enable customers to access the flexibility market, it is necessary to install:

  • a second-generation meter
  • a device called a light node, required to receive activation com- mands and certify energy transfers.

In addition, to increase flexibility, micro-photovoltaic plants have been installed for certain customers, equipped with batteries.

The Italian project, launched in July 2021, will contribute to the cre- ation of an integrated and efficient local ancillary services market, with implementation of advanced IT technology enabling prosumers to sell or purchase electricity entirely automatically.


The G.I.M.M.I. project (Massive and Targeted Infrastructure In- spection Management) is an innovative end-to-end solution combining satellite monitoring, artificial intelligence (AI) and drones in a single system. The satellite platform enables Areti to periodically acquire images of HV and MV overhead lines. These are process- es and analysed by an algorithm using AI technology that enables identification of human or plant interference. Once interference has been identified and classified on the basis of the level of severity, it is possible to launch targeted inspections using drones.

Implementation of these systems for HV and MV grids offers multiple benefits. The quick response and precision of information enables specific inspections in place of mass cyclical inspections, thus reducing the number of inspections, increasing their efficacy and reducing working times, supporting prevention or quick resolution of outages, to the benefit of many customers and the operator. For example, controlled and targeted pruning of vegetation can prevent events that would lead to potentially serious damage to the grid. In addition, the reduced impact of motor vehicles and elimination of helicopter flights for cyclical inspections contributes significantly to reducing CO2 emissions.

The project, launched in 2021, involves GMatics, a start-up offering satellite monitoring and analysis services using AI algorithms. It is also monitored by the Drone Observatory of the Politecnico di Milano university, which has the task of analysing, mapping and providing indications of current and future trends for drone applications. An upgrade is currently being studied for the creation of automatic work orders on company SAP systems, enabling planning of inspections, guaranteeing traceability and filing on the system.