Under the cross-border cost allocation and financing arrangements agreed by ARERA and CRE, EDF is scheduled to make a significant lump-sum payment to Terna in 2025 as part of its 45.5% contribution to Terna’s SACOI 3 CAPEX, a transfer that the regulators note will already partly address the project’s rising costs and financing complexities.
EDF, which operates the Corsican electricity grid, has started onshore construction of the new Sa.Co.I.3 HVDC conversion station at Lucciana in Corsica, marking a new phase in modernising the interconnection between Sardinia, Corsica and Italy. The works were formally launched with a ceremonial laying of the first stone at the Lucciana electrical substation site on 11 September 2025, attended by regional authorities, EDF, CRE representatives, project partners, and Terna’s Executive Vice President for Engineering and Project Execution.
Construction of SACOI 3’s land‑based sections began in early 2025, marking the start of onshore works for the new bipolar multi‑terminal HVDC interconnector linking Suvereto (mainland Italy), Lucciana (Corsica) and Codrongianos (Sardinia). This phase follows public consultation activities held in December 2024 and early 2025 and includes civil works for new converter stations and associated onshore cable routes, with the overall project reported as under construction in EU PCI documentation and accompanied by a foundation‑stone ceremony at the Lucciana converter station site in September 2025.
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Sa.Co.I.3 (commonly written SACOI 3) is the planned replacement and upgrade of the existing Sardinia–Corsica–Italy HVDC link (SACOI) designed to renew end-of-life assets and increase transfer capability between mainland Italy, Corsica (France) and Sardinia (Italy). The project will install a bipo...
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Sa.Co.I.3, SACOI3, SaCoI3, PCI 1.10, Project 299 - SACOI3, ENTSO-E project code P0299, PCI reference 299-1458
On 30 December 2024, ARERA and CRE issued a coordinated decision on the SACOI 3 investment request, agreeing a cross-border cost allocation whereby EDF covers all assets dedicated solely to supplying Corsica and 45.5% of the CAPEX for Terna-operated works, while Terna bears 54.5%; the decision confirms that SACOI 3 investment costs to be borne by Terna will be included in regulated tariffs in Italy and France, based on a project appraisal that quantifies present-value CAPEX of €685 million for Italy and €972 million for France and shows substantial net benefits for both countries.
On 30 December 2024, the Italian and French regulators ARERA and CRE issued a coordinated decision on SACOI 3, agreeing a cross‑border cost allocation in which EDF covers all assets dedicated to Corsica and 45.5% of Terna’s CAPEX (with Terna bearing 54.5%), and confirming that Terna’s SACOI 3 investment costs will be included in Italian transmission tariffs.
In October 2024, Terna S.p.A. and EDF S.A., as promoters of the SACOI 3 interconnector, submitted an investment request to the Italian and French National Regulatory Authorities (ARERA and CRE) under Article 16 of Regulation (EU) 2022/869, seeking a decision on cross-border cost allocation between France and Italy and inclusion of the project’s costs in national tariffs; the request was supported by project-specific cost estimates, a cost–benefit analysis and a business plan, with Terna’s assets alone estimated at about €1,350 million.
Terna and EDF selected Hitachi Energy to supply the high-voltage direct current (HVDC) converter technology for the Sa.Co.I.3 interconnection, using its HVDC Light (VSC) solution in a 400 MW bipolar, multi-terminal configuration that will replace the existing equipment between mainland Italy, Corsica and Sardinia. Hitachi Energy will collaborate with civil contractors Pellegrini and Razel-Bec for the civil and installation scope of the project.
On 28 May 2024, EDF announced that the tender for the construction of three new converter stations for the SACOI3 interconnection project—located in Sardinia, Corsica and Tuscany—was awarded to the Hitachi Energy/Razel bec/Pelligrini consortium, marking the appointment of the main construction and installation contractor for these facilities.
Terna (and EDF) awarded the Sa.Co.I.3 submarine cable supply and installation contract to Prysmian Group in May 2024 as part of the full EPCI package covering the Suvereto-Lucciana-Codrongianos HVDC link. Date matches existing epci_contract_awarded milestone.
On 28 May 2024, EDF and Terna finalised the main contractual arrangements for the Sa.Co.I.3 HVDC interconnection, effectively reaching the Final Investment Decision for the project. EDF signed a long-term cross-border cost-sharing contract with Terna for the Sardinia-Corsica-Italy link and simultaneously awarded construction contracts covering the Corsican scope, while Terna concurrently awarded the main EPCI contracts — to Prysmian Group for the two HVDC submarine cable systems (105 km Suvereto-Lucciana + 16 km Lucciana-Codrongianos at 200 kV, two poles each) and, a few days later on 31 May 2024, to Hitachi Energy for the three HVDC converter stations (Suvereto in Tuscany, Lucciana in Corsica and Codrongianos in Sardinia). As with other TSO-led interconnections (e.g. Cyclades Phase D and Bay of Biscay), Terna has no traditional external project-finance FID moment; the combined EPCI contract signings and the EDF-Terna cross-border cost agreement together commit the capital and function as the effective financial close for the SACOI 3 programme, which is financed through Terna's regulated CAPEX with ~45.5% contribution from EDF under the ARERA/CRE cross-border cost allocation arrangements and partial REPowerEU co-funding.
On 15 May 2024, the European Commission’s first PCI/PMI list under the revised TEN-E framework confirmed the interconnection between mainland Italy, Corsica and Sardinia (currently known as SACOI 3) as electricity PCI 1.10, describing it as an under-construction 400 MW HVDC link replacing SACOI 2, with planned commissioning by 31 December 2027.
On 21 December 2023, the French energy regulator CRE adopted deliberation 2023-363, establishing the regulatory treatment of the Lucciana HVDC converter station and EDF’s contribution to Terna’s CAPEX for SACOI 3, confirming that the costs of EDF-operated SACOI 3 assets are regulated in France.
Italian (MASE/AIA) and French environmental and planning authorisations finalised around Dec 2023 enabling Terna/EDF to proceed with construction of the Sa.Co.I.3 HVDC link between Suvereto (IT), Lucciana (Corsica, FR) and Codrongianos (Sardinia, IT). Date matches existing regulatory_other milestone. Restored with approximate precision after earlier no-date extraction was cleaned up.
On 8 November 2023, Terna announced that the Autonomous Region of Sardinia had formally approved the SACOI 3 interconnector project, as part of a package of three key projects for the Sardinia electricity grid. This regional approval is described as a decisive step that closes off the regional authorisation process for SACOI 3 and enables the final stage of the authorisation process with the Ministry of the Environment and Energy Security.
For the Sa.Co.I.3 interconnection project, the Prefect of Haute Corse granted the Single Environmental Authorization (Autorisation Environnementale Unique) for the works in the Corsican area by signing it on 2 August 2023, following completion and approval of the public inquiry phase earlier in 2023.
Following the Public Inquiry phase for the Corsican section of the Sa.Co.I.3 interconnection, the Prefect of Haute Corse signed the Declaration of Public Utility (Déclaration d’Utilité Publique) for the Sa.Co.I.3 works on 20 July 2023, formally granting this activity-specific authorisation. This decision concerns the works in the Corse area associated with the new Sardinia–Corsica–Italy HVDC connection promoted by Terna.
In Corsica, following the preliminary investigation process for the Sa.Co.I.3 project, a formal Public Inquiry (enquête publique) was held from 27 March to 6 May 2023, with public meetings organised in the municipalities of Lucciana, San Giuliano, Lecci and Bonifacio. This consultation phase invited local stakeholders to review and comment on the proposed corridors and works for the Sardinia–Corsica–Italy interconnection.
By the time of ENTSO-E’s TYNDP 2022, SACOI 3 (Project 299) was again assessed in the plan, with the project fiche used to quantify socio-economic welfare, CO2 reduction and security-of-supply benefits for France and Italy under several 2030 and 2040 scenarios.
By the time of Terna’s 7 April 2022 press release, the Environmental Impact Assessment for the Sa.Co.I.3 interconnection project had been approved through the issuance of an Environmental Compatibility Decree by the competent ministerial departments, following updates to the project that emerged during the EIA process.
In May 2021, Terna concluded a design contest for Sardinian professionals and businesses to design the new Codrongianos HVDC conversion substation in Sardinia and officially announced the “Is Lampadas” project as the winning proposal, thereby selecting the architectural designer for a sustainable, low-impact station that blends harmoniously into the surrounding agricultural landscape.
EDF and Terna prepared and published the SACOI 3 public consultation dossier (dossier de concertation) for Corsica, marking the start of formal stakeholder engagement on the project’s renovation of the Sardinia–Corsica–Italy HVDC link and associated works at Lucciana.
Terna Rete Italia S.p.A. submitted an application on 9 August 2019 to initiate the Environmental Impact Assessment (VIA) procedure for the SA.CO.I.3 project, covering the renewal and upgrade of the HVDC Sardegna–Corsica–Italia interconnector in the municipalities of San Vincenzo, Santa Teresa Gallura, Piombino, Codrongianos and Suvereto in the provinces of Olbia-Tempio and Livorno, to the competent Division V of the ministry.
Terna launched the consultation procedure for the Sa.Co.I.3 project with the Italian municipalities involved in September 2018, initiating a participatory planning process. As part of this, it organised a series of five “Terna Incontra” public meetings, held through to September 2021 in the municipalities of San Vincenzo, Suvereto and Piombino in Tuscany and Codrongianos and Santa Teresa di Gallura in Sardinia, to present the new infrastructure and gather feedback from local authorities and the public.
In 2017, the SACOI 3 interconnection project was labelled a Project of Common Interest (PCI) by the European Union, recognising the reinforcement of the Sardinia–Corsica–Italy HVDC link and the new Lucciana converter station as strategic for Corsica’s power supply and regional energy policy objectives.
On 6 December 2016, SACOI 3 (Project 299) was included in ENTSO-E’s TYNDP 2016 as a long-term HVDC project between mainland Italy, Corsica and Sardinia, intended to replace the ageing SACOI 2 link, increase transmission capacity and enhance security of supply and RES integration.
By December 2016, SACOI 3 (Project 299 in ENTSO‑E’s TYNDP 2016) was in the design phase as a new HVDC link between Codrongianos (Sardinia) and Suvereto (mainland Italy) to replace the existing SACOI2 scheme, classified as a long‑term project with a target commissioning date of 2023 and an indicative 2015 CAPEX of about €700±50 million including the Corsica converter station.
In 2015, the Collectivité de Corse adopted its regional multi-annual energy plan (Programmation Pluriannuelle de l’Énergie, PPE), which identifies increasing the power withdrawn over the SACOI link and renewing the Lucciana converter station—implemented through the SACOI 3 project—as structural measures to secure Corsica’s electricity supply and support energy transition.
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