Energy production: fossil and renewable energy sources

GROUP PLANTS

Through Acea Produzione and Acea Ambiente, the Group generates electricity primarily from renewable sources. The majority of production is provided by hydroelectric plants and another significant portion, also partially renewable, from waste-to-energy plants utilising paper-mill waste and Solid Recovered Fuel (SRF).
Acea also launched a major programme to increase its activities in the photovoltaic sector, in line with the 2020-2024 Business Plan, which plans for an installed capacity of around 750 MW through acquisitions and the construction of new plants. As of March 2022, this aim has been supported by a financial transaction under which Acea transfers its existing photovoltaic assets — which are either already in operation or in the process of being connected to the grid — to a Company of which Acea Produzione is a minority shareholder¹⁶⁴, while retaining control of the management of the plants, and has signed agreements aimed to purchase the renewable energy produced by the plants.

Lastly, Acea Produzione has generation plants from fossil fuel (thermoelectric) – the latter mainly through the high-efficiency cogeneration plant of the Tor di Valle plant, which had greater availability during the year.
The power park includes:

• 7 hydroelectric power stations located in the Lazio and Abruzzo regions for a total of 122 MW;
• 2 thermoelectric power stations located within the Municipality of Rome area: Montemartini (78.3 MW)¹⁶⁵ and Tor Di Valle (28.5 MW), for 8 MWe total available installed capacity;
• a photovoltaic park for a total of 8 MW¹⁶⁶ (total capacity, including the plants owned by the investee company and not consolidated on a line-by-line basis, is 100.6 MW).

The generation of energy from waste-to-energy processing is managed by Acea Ambiente, taking place at two plants located in San Vittore del Lazio and Terni, and both with percentages of biodegradable material (renewable source) varying between 40% and 50%. The total gross electrical power currently available is approximately 58 MWe.
In addition, the Environment Segment produces electricity using biogas derived from the anaerobic digestion process at the Orvieto Technology Hub, the sites managed by Deco and the composting plants of Aprilia and Monterotondo Marittimo.
The Company Ecogena, certified as an ESCo (Energy Services Company) in accordance with UNI CEI 11352:2014, develops the energy efficiency initiatives for the Group and reports their results to Gestore dei Servizi Energetici (GSE) for the awarding of Energy Efficiency Certificates (EEC).
The activities assigned to Ecogena include also the design and building of cogeneration and trigeneration plants¹⁶⁷ for the combined production of electricity, heat and cooling energy.
The total production capacity of the cogeneration plants managed by Ecogena, combined (or not) with district heating networks, amounts to a total electrical output of 1.9 MW, located in areas across the Lazio region.

Table no. 51 – Installed power of the electric power stations of Acea Produzione

(*) The CAR plant in Tor di Valle provides district-heating service in the area south of Rome.

Installed capacity, which totals168 around 305 MW (398 MW including the Investee company not consolidated on a line-by-line basis), is represented in Chart no. 50, broken down by energy source.

Chart no. 50 – Installed power of Companies included in the NFS divided by energy source (MW) (2022) (2022)

ELECTRICITY PRODUCED

In 2022, total gross electricity production fell by 17%, from 1,016 GWh in 2021¹⁶⁹ to 842 GWh in 2022 (941 GWh, including energy produced by the photovoltaic plants of the subsidiary not consolidated on a line-by-line basis).
The reduction is mainly due to the lower rainfall in the year, which impacted hydroelectric energy production (down 23%). Biogas production increased by 16%, partly due to the inclusion in the reporting scope of Deco (without this, the increase would have been 7%). For further details, see the Environmental Accounts.

Electricity generated from renewable sources, amounting to approximately 538 GWh (636 GWh including the photovoltaic plants of the subsidiary not consolidated on a line-by-line basis) represents the majority at around 64%¹⁷⁰, with the following contributions:

• 3 GWh from hydroelectric power,
• 6 GWh from waste-to-energy,
• 3 GWh from biogas (Orvieto, Deco¹⁷¹, Aprilia and Monterotondo Marittimo waste management plants)
• 5 GWh from photovoltaic plants¹⁷² (111.9 GWh including the plants of the subsidiary not consolidated on a line-by-line basis), see Chart no. 51 and Table no. 52.

After the completion of upgrading and energy efficiency measures in 2022, the revamping of the Sant’Angelo power plant was completed, with the goal of optimising the use of available water resources, with the same specifications in terms of installed power and authorised by concession.

A significant portion of the energy from waste-to-energy production, as already noted, is associated with the combustion of the biodegradable fraction of waste used as a primary source. In particular, the renewable share of the fuel (SRF) of the San Vittore del Lazio plant was 46.8% of the total of waste-to-energy in 2022, while at the Terni plant this share was 40.8%.

Chart no. 51 – Electricity produced subdivided by primary energy source (TJ) (2022)

NOTE: the values reported in the chart are expressed in TJ (1 GWh=3.6TJ).

Table no. 52 – Electricity produced (by primary energy source) (2020-2022)

(*) 1 GWh = 3.6 TJ.
(**) Photovoltaic energy includes the production at the plants located on sites of the water area (Acea Ato 2 and Acea Ato 5) and in Orvieto, for a total of 1.7 GWh produced. Natural gas includes production by Ecogena.
(***) Including the data from the photovoltaic plants of the subsidiary not consolidated on a line-by-line basis, the 2022 data would be solar photovoltaic 402.8 TJ (111.9 GWh), total renewables 2,290.0 TJ (636.1 GWh), overall total 3,387.1 TJ (940.9 GWh).

THERMAL ENERGY PRODUCED

Total thermal energy produced in 2022 was 105.3 GWh.
The Tor di Valle thermoelectric power plant generated 87.7 GWh of thermal energy.
The heat generated was used to serve 40,794 residents in the area south of Rome (Mostacciano, Torrino and Mezzocammino) by means of a district-heating network which provides a volume equal to 3,668,967 cubic metres.
This thermal energy is supplemented by the 17.6 GWh produced by the Ecogena plants in 2022.
For production data for the three-year period for Acea Produzione and Ecogena, see Products in the Energy section of the Environmental Report.

164 In particular, this refers to AE Sun Capital Srl, established in January 2022, and 40% owned by Acea Produzione and 60% by the investment fund Equitix Investment Management.
165 The power station is operational only in the event of extraordinary energy demand, and operation can also be managed remotely from the control room at the Tor di Valle Power Station.
166 Output of the Acea Produzione, Acea Solar, Acea Renewable and SF Island plants.
167 Cogeneration, i.e. the combined production of electrical and thermal energy, allows high eciencies to be achieved, between 80 and 90%. Trigeneration, which is a special application of cogeneration, allows use of a part of the thermal energy recovered in order to produce cooling energy in the form of cooled water for air conditioning in rooms or for industrial processes.
168 Total installed power includes the plants operated by Acea Produzione, Ecogena, and Grasciano 2 plants) and Deco for the production of biogas.
169 The data for Ecogena, previously reported separately, is now included in the 2021 data.
170 68% if including the photovoltaic plants of the subsidiary not consolidated on a line-by-line basis.
171 The Deco plants, which joined Acea Ambiente in 2022, produced 2.7 GWh.
172 This does not include the energy produced by two photovoltaic plants operated by Ad Fand the Terni waste-to-energy plant, which produced 12.8 and 454.3M Whre spectively, mainly for self-consumption.