Atmospheric emissions

Atmospheric emissions from production activities are monitored in a planned and constant manner. The plants are managed according to UNI EN ISO 14001 and UNI EN ISO 45001 management standards. Acea Ambiente also applies the UNI EN ISO 50001 management system, while the waste-to-energy plants, the Orvieto Ambiente plant and the Deco and Ecologica Sangro sites are also registered under the European EMAS III scheme, extended until 2024²³⁹.

The main macro-pollutants from the Acea Ambiente and Acea Produzione plants, are monitored through Continuous Emission Monitoring Systems (CEMs). In 2023, macro-pollutants were recorded at very low values and are decreasing compared to previous years (see Table 68).

Table no. 68 – Total atmospheric emissions of pollutants from the main Group plants (2021-2023)

Note: the emissions refer to the plants of Acea Ambiente – waste-to-energy and Acea Produzione.

Specifically, monitoring conducted at the waste-to-energy plants is carried out using fixed and mobile stations that sample and analyse the fumes coming out of the chimneys, measuring concentrations for multiple parameters that are periodically checked by internal personnel and certified by qualified external laboratories. As in previous years, in 2023, these concentrations were significantly below the legal limits (see Table No. 69).

At the San Vittore del Lazio plant, the monitoring campaigns carried out for PM10, PM2.5²⁴⁰, heavy metals (fixed and mobile survey stations) and PAHs (polycyclic aromatic hydrocarbons), dioxins and furans (mobile only) did not detect any critical values. Other actions in the year including the monitoring of diuse and fugitive emissions and the continuation of a biomonitoring campaign using bees as bi- oindicator insects (see Safeguarding of Land and Biodiversity, in the chapter Environmental Sustainability and the Main Challenges). Fi- nally, each waste-to-energy line has systems to monitor emissions from the chimney, enabling continuous tracking for concentrations of pollutants 24/7, with availability of data on the Group website (www.gruppoacea.it).

Environmental monitoring is carried out at all plants. For example, at the Aprilia plant, an experiment was conducted using drones and the “Acea Nose” control unit. At the same time, a ground survey campaign was undertaken on certain parameters, including hydrogen sulphide (H&S), odours, volatile organic compounds (VOC),nitrogen oxide (NO₂) and methane (CH₄), etc. The outcome of this campaign found that the impact of the relative composting plant on the surrounding urban areas was zero in terms of gas and odour emissions.

Table no. 69 – Concentrations of atmospheric emissions generated by waste-to-energy plants (2021-2023)

(*) The analysis of PAH, dioxins and furans and heavy metals and their composites are four-monthly and discontinuous. The “<” symbol identifies the concentration values that are equal to or below the thresholds that the devices used by the laboratory are capable of measuring.
(**) Reference parameters, Legislative Decree no. 46/2014, 2000/76/EC and IEA, are separate for each waste-to-energy plant.
Note: For San Vittore del Lazio, over the years the recorded concentrations of the parameters HCl, SO&, dust and HF were close to the instrument’s detection limit. Therefore, in these measurement areas deviations are to be considered insignificant for absolute changes in concentrations and masses.

Monitoring carried out on installations at risk²⁴¹ has shown the absence of emissions in significant quantities of substances responsible for reducing the ozone layer (for consumption see the section Resources used, in the Environmental accounts).

GREENHOUSE-GAS EMISSIONS

CO₂ emissions are quantified by monitoring and evaluating the carbon footprint of the individual macro production processes according to the guidelines of the GHG protocol²⁴² which requires reporting in the direct (Scope 1) and indirect (Scope 2 and Scope 3) categories.

Direct Scope 1 emissions mainly come from the Group’s two waste-to-energy plants and the thermoelectric power stations. As of 2022, two plants are subject to the Emission Trading Scheme (ETS), specifically the Montemartini and Tor di Valle power stations. As of March 2022 and with retroactive²⁴³ effect, the Terni waste-to-energy plant is no longer included in the scope of appli- cation of the ETS Directive.

The allowances assigned according to the NAP (National Alloca- tion Plan) are lower every year and essentially very small, compared to the actual emissions recorded. Data for the three-year period 2021-2023 is presented Table no. 70.

Table no. 70 – CO₂ emission allowances as per the National Allocation Plan (NAP) and actual emissions by plant (2021-2023)

(*) As with previous years, in 2023 the applicable legislative framework allowed the Tor di Valle plant to benefit from free of charge emission allowances (3,380 t) as it serves a district-heating network.
(**) The 2022 figures for actual emissions have been updated with the certified figures.
(***) Estimated emissions, pending certification by the responsible body.

Scope 1 emissions include other components deriving from certain processes of plants in the Environment Segment (composting, treatment and disposal of liquid waste), from drying at treatment plants, from petrol and diesel vehicles in the fleet, from leaks of sulphur hexafluoride (SF6) that may arise at Areti plants, from combustion processes for heating of premises and offices, and finally from leaks of freon gases from air-conditioning units.
The amount of CO₂ emitted by waste-to-energy plant in 2023 decreased compared to 2022, by -13% (see Table no. 71); this was mainly attributable to the stoppage of the Terni plant in Novem- ber, which had in fact produced less electricity compared to 2022 (-17.5%).
The reduction in the CO₂ emissions also produced by Acea Produzione thermoelectric power stations refers to lower production of thermoelectric power, and consequently, to less use of fuel; the other Scope 1 emissions were essentially stable in relation to 2022.

Scope 2 greenhouse gas emissions from electricity consumption in 2023 were down compared to 2022 (approximately -6%). Rendering the water business more efficient, for example, combined with lower consumption due to less pumping, due to more abundant rain- fall and more intense usage of gravity-based water sources, all contributed to this improvement. For more details see the paragraph on Energy Saving. Emissions due to technical losses on the electricity network came down (by about -5%) due to reduced demand on the network (-2.6%) and interventions to increase efficiency.

Scope 3 emissions (see Table no. 71) include those deriving from gas and electricity sales, electricity consumption by suppliers of purchased goods, services and works, business travel and the main subsidiaries²⁴⁴ (Scope 3 category “Investments”).
In 2023, similarly to the previous year, business travel emissions rose again, with the end of the restrictions caused by the pandemic and resumption of normal business travel, also considering that less employees were working remotely over the last year.
Scope 3 emissions associated with the purchase of goods, services and labour are calculated using monitoring data for energy consumption outside the Group, requested from a representative panel of suppliers using a questionnaire (see the section Energy consumption outside the Group). In particular, the data requested refers to energy (consumption of fuels, electricity and vehicle fuels) and data relating to refrigerant gases used in-house, which contribute to this category of Scope 3.

To reduce emissions from electricity sales (calculated in the table using both the location-based and market-based methods), Acea Energia offers customers GO-certified green electricity commercial rates. Since 2021, all new retail customers on the free market are exclusively offered GO-certified green energy, with the gradual roll-out to contracts signed before this date. The “sustainable” rate also covers gas thanks to osetting through the purchase of VER (Verified Emission Reduction) certified carbon credits. The carbon credits purchased for 2023 contributed to funding projects to reduce carbon dioxide emissions in Peru and Vietnam with tangible benefits for the local communities. See also the Chapter Customers, paragraph Customer care.

In 2023, Acea Energia sold more “green” energy²⁴⁵, to customers on the free market, estimated at 3,000 GWh, increasing by over 18% compared to the volumes consolidated in 2022 (at 2,536 GWh). The share of this item out of the total energy sold in the year to free market customers (around 5,369 GWh, see also Environmental Accounts) reached 56% (42% on the 2022 consolidated figures).

The sale of electricity with GO certification has therefore led to a saving of approximately 945,000 t of CO₂ in the Scope 3 category. For gas sales in 2023, offsetting measures are expected to cover approximately 120 MSm3 (estimated figure; 54 MSm3 in 2022), corresponding to approximately 238,900 t of CO₂.

INTENSITY INDICES FOR GREENHOUSE GAS EMISSIONS

The emissions intensity index linked to value added improved, decreasing by 15% compared to 2022. Total Scope 1 plus Scope 2 emissions came down by 9%, while value added increased by 7% (see Table 71). The performance of the Scope 1 emissions on energy produced (-20%)²⁴⁶ improved. The indicator stands at 366.1 g/kWh (326.2 g/kWh considering also the photovoltaic production of the subsidiary not consolidated on a line-by-line basis), with a decrease due to increased electricity production from hydroelectric (+27% compared to 2022 production) and the reduction in Scope 1 emissions already referred to. The indices for greenhouse-gas emissions under Scope 2, resulting from losses on the electricity distribution networks compared to the total electricity issued, recorded a decrease of around 2% compared to 2022: going from 0.0088 t/ MWh (updated figure after consolidation) to 0.0086²⁴⁷.

Table no. 71 – Environmental indicators: CO₂ emissions, greenhouse gas intensity indices (2021-2023)

Note: come figures for 2022 have been restated after consumption calculations. Emission factors for Scope 1 emissions are taken from the standard parameters – ISPRA data 2023, DEFRA 2023 and GHG Protocol-5th Assessment Report-AR5.
(*) The 2022 figures for the Tor di Valle and Terni plants have been adjusted after the ETS certification, while the 2023 figure is estimated pending certification by a third-party body for Tor di Valle and the definitive analyses for Terni.
(**) The figure includes the emissions of the ancillary services of the waste-to-energy plants, not strictly related to the production of electricity, of Acque Industriali, Aquaser, Berg and Demap.
(***) Data refers to uses of dryers and generators.
(****) These are the tonnes of equivalent CO& corresponding to the emissions of insulating SF6 present in Areti’s HV equipment (1 t of SF6 equates to 23,500 t of CO&, GHG Protocol-5th Assessment Report- AR5).
(*****) In the last three years, the replenishment of HCFC fluids in the Group’s plants was so small that it did not lead to significant CO& emissions.
(******) The indirect emissions (Scope 2) include all the Companies within the NFS scope. As an emission factor per unit of electricity consumed (t CO&/MWh), for the loca- tion-based calculation the value of 0.315 was used for the three-year period, as per Terna’s “International Comparisons” document. For the calculation of Scope 2 emissions using the market-based method, the residual mix coecients are the following for 2021, 2022 and 2023, respectively: 0.4586, 0.4566 and 0.4572 (Source: AIB document “European Residual Mixes”). Emissions due to technical network losses in 2022 were restated, whereas the figure for 2023 was estimated.
(*******) As of 2022 emissions from commuting are not calculated as the values are negligible.
(********) This value, estimated, refers to suppliers of goods, services and works. The 2023 figure is broken down as follows: 25,240 tonnes of CO& for suppliers of services and works and 4,943 tonnes of CO& for suppliers of goods.
(*********) Scope 1 emissions included are those from power generation plants, including Ecogena. If the photovoltaic production of the investee company not consolidated on a line- by-basis were also taken into account, the indicator for the year would be 326.2 g/kWh.

239 In the case of Deco, the EMAS registration is valid from 2022 to 2025.
240 PM10 refers to particles with a diameter less than or equal to 10 μm. The term PM2.5 refers to particles with a diameter less than or equal to 2.5 μm.
241 This is primarily air conditioning equipment using refrigerant gases subject to the 1987 Montreal protocol, particularly chlorofluorocarbons.
242 See www.ghgprotocol.org for more information.
243 In March 2022, following an exemption request submitted to the MISE, with Resolution 66/22 the National Committee for the management of Directive 2003/87/EC and for support in the management of project activities of the Kyoto Protocol, determined, with retroactive effect, the exclusion of the Terni plant as of 31 December 2020.
244 Acque, Publiacqua and Umbra Acque.
245 As in previous years, the figure for G.O. certified green energy sold in 2024 by Acea Energia and AEMA also includes the main Group companies’ internal consumption (contributing for around 316 GWh).
246 The index is calculated using emissions from production (Acea Produzione's thermoelectric power stations, Ecogena plants, waste-to-energy plants) as numerator and total energy produced by the Group's plants as denominator.
247 The figure is estimated.