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The extra-high voltage direct current (HVDC) Piossasco - Grande Ile connection between Italy and France is a strategic project, not just for the two countries themselves, but for Europe as a whole since it contributes to the creation of North-South infrastructure corridors for the transmission of electricity affecting the European Union.

For this reason, according to Regulation (EU) 347/2013, in 2013 the project was added to the list of Projects of Common Interest (PCIs).

This document complies with the provisions of Regulation (EU) 347/2013, which requires — in particular in Art. 9 “Transparency and public participation” — that the promoter of the project creates, and regularly updates, a Website site containing all pertinent information regarding the project of common interest (e.g. technical description of the project, its progress, information on the authorisation process undertaken, benefits of the project, etc.); the site contains a link to the European Commission’s website and meets the requirements laid out at point 6 of Annex VI of the Regulation itself, where pertinent for progress of the project.

It is understood that, through its own website, Terna will periodically update information regarding the progress of the project for the benefit of all stakeholders.


  • Overview of the project

    On 30 November 2007, to strengthen security and integration of supply and market competitiveness in line with the European strategy for augmenting interconnections between Member States, the Italian and French Governments signed an agreement to boost interconnection capacity.

    The TSOs, Terna and RTE — respectively, the Italian and French power transmission grid operators — began joint study and planning of the network developments required to achieve the common goal of increased crossed-border transfer capacity.

    The work — which envisages construction of the new HVDC line between the Piossasco (Piedmont) and Grande Île (Sainte-Hélène-du-Lac, Savoie) power stations — was first included in the 2008 Development Plan for the National Transmission Grid (RTN). The work is envisaged as completion of a plan of action, object of a study (TEN-E 183/04) co-financed by the European Commission, aimed at increasing the transmission capacity between Italy and France by adapting/optimizing the existing infrastructures.
    Not only will the new interconnection strengthen the exchange capacity and electrical solidarity between France and Italy; it will also contribute to development of the European power grid and thus transition towards broader use of renewable sources.
    The feasibility study for the new interconnection line — to be implemented using motorway infrastructures — was then the object of a specific study (TEN-E 221/07), again co-financed by the European Commission.

    At present, electricity exchanges between France and Italy can rely on existing alternating current lines (the Terna 380 kV double line Rondissone - Albertville, the 380 kV Venaus - Villarodin line and the 220 kV Camporosso - Trinité Victor/Mentone d.c. line) with a maximum exchange capacity of approximately 3150 MW and which are at full capacity most of the time.

    It has therefore become necessary to increase the exchange capacity between Italy and France, boosting mutual assistance between the two and pooling the generation resources and grid services available for the two countries and the overall European system.

    Completion of the new Italy-France HVDC interconnection, expected by December 2019, will increase the transport capacity between the two countries by 1200 MW, reaching a maximum exchange capacity of 4350 MW, an increase of around 40%.
    The intervention is also included in the ENTSOE’s TYNDP starting in 2010 and, as mentioned above, since 2013 has been included on the first list of Projects of Community Interest (PCIs) under Regulation (EU) 347/2013, code 2.5.1 Interconnection between Grande Ile (FR) and Piossasco (IT) [currently known as “Savoie-Piemont” project], under the Priority Corridor North-South Electricity Interconnections in Western Europe. The project was included in the second PCI list and was also confirmed in the third PCI list, recently published on the site of the European Commission. For further details see the information posted on the European Commission platform at link.

    The European Investment Bank (EIB) is contributing approximately € 300M to finance the work.
  • Main benefits of the project

    The realization of the new interconnection between Italy and France stands on the increased integration of these two markets. Historically, interconnections with France mainly featured energy flow to Italy given the evident differences in the mix of generation systems — and thus wholesale prices — between the two countries. The high utilization of capacity currently available and the prospective studies performed have led us to assume that the creation of a new cross-border connection will further increase such flows and reduce the price gap between the two markets.

    With regard to supply security and continuity, the new interconnection will ensure better distribution of flow over the power lines, thus enhancing system adequacy. Operating safety will also be improved, thus ensuring increased system stability and greater operational flexibility.

    The additional 1200 MW between Italy and France — increasing transmission capacity on the northern Italian border by about 15% — will reduce grid congestion, helping to boost electricity imports and exports and improve integration of renewable sources. In addition, realization of this project will enable Italy to home in on the 2020 target of an overall interconnection capacity approaching 10% of the installed generation capacity.

     An in-depth analysis of the project — performed by ENTSOE as part of its 2016 TYNDP — has also shown that the 2030 target for increased transmission capacity over the northern Italian border exceeds 13.5 GW, thus requiring that all projects planned be implemented, including this Italy-France project which is the most relevant and also the one at the most advanced stage.

    As shown in Figure 1 below, the results of the Cost Benefit Analysis (CBA) presented in the 2016 TYNDP show that the Italy-France project - with a total cost (including both the Italian and French parts) of around € 1.2 billion - significantly increases the socio-economic benefits of the pan-European system in terms of Social Economic Welfare (SEW) as related to energy exchanges both in the medium- (EP2020 scenario) and long-term (Vision 2030); moreover it also integrates production from renewable sources and reduces climate-altering emissions, keeping the scenario on tract to reaching the European Union decarbonization goals for 2050.

    Figure 1 – TYNDP 2016 - CBA Analysis (December 2016)

    As regards the Grid Development Plan, assessment has shown that the benefits offered by the project are highly positive in terms of both the increase in SEW for the Italian system — considering that the new interconnection entails reduced procurement costs and electricity market purchase prices — and in RES integration — given the greater operating flexibility that can balance the system without needing to reduce production from non-programmable renewable sources..

    Figure 2 - PdS 2017 (Dec 2016)

  • Interconnector project funded by private subjects selected under Law 99/2009

    In order to support development of a single electricity market by strengthening the international interconnection infrastructure, European Union legislation has laid out guidelines for the creation of interconnections with foreign countries by parties other than grid operators.

    Italian law has transposed the European guidelines into Article 32 of Law 99/2009 which, in contributing to the creation of the single electricity market, has established that, in the presence of specific loans and under specific mandates from third-party investors, the company Terna will plan, construct and operate one or more expansions of the interconnection infrastructures with other countries and that this will take the form of an interconnector (under the terms of Regulation (EC) No. 1228/2003), that will make available a total increase of up to 2500 MW in overall transport capacity between Italy and foreign countries.

    In this context, the Italy-France Interconnector is the first contribution — with the capacity of 350 MW assigned essentially to private investors — to achieving the goals set by Law 99/2009.

    The intervention falls under the creation of the direct current Piossasco (IT) – Grande Ile (FR) connection — 1000 MW total (with maximum power capacity of 1200 MW) — consisting of two HVDC bipolar lines. While, on the French side, the entire investment is public (owned by the French TSO RTE), on the Italian side, only one of the two bipolar lines is public, under Terna, while the other is owned by private investors throughout the entire exemption period.

    On 27 March 2015, under the mandate of the selected assignees pursuant to Law 99/2009, the Terna Group established the vehicle company Piemonte Savoia S.r.l. (PI.SA.) which, on 12 June 2015, submitted to the Ministry of Economic Development (MiSE) an application for exemption pursuant to Article 17 of Regulation (EC) 714/2009.
    On 12 May 2016, after consultation with the French Regulatory Authority (CRE), the AEEGSI issued its own opinion with Resolution 228/2016/I/eel. The CRE also expressed its own opinion in the Resolution issued on 12 May 2016, referring to the AEEGSI decision and expressing its agreement with the AEGGSI opinion.

    On the basis of these opinions, on 20 July 2016 the MiSE issued the Decree of Exemption, with MiSE Managerial Decree no.290/ML/6/2016. This decree provides a ten-year exemption period — starting the moment the connection begins commercial operations — during which a 7/12 share of the total congestion-generated revenues available to Italy (corresponding to a maximum capacity of 350 MW) will be transferred to PI.SA. It also stipulates that, before the Interconnector becomes operational, the entire PI.SA. share capital is to be surrendered to the recipient (Terna must no longer hold any share in the Company) and that, at the end of the exemption period, ownership of the new Interconnector shall be transferred to Terna.

    The MED Decree of Exemption was sent to the European Commission (EC) for its assessment and opinion. On 09 December 2016, the EC issued its own favourable opinion on the Decree of Exemption with Final Decision no. C(2016) 8592. Consequently, on 06 April 2017, MiSE notified successful completion of the procedure on behalf of PISA and thus the 90-day (statutory) deadline for the transfer of PI.SA to the private investors and for stipulation of the mandate contracts for construction and operation of the project starts from this date.

    On 4 July 2017, the Terna group and the consortium Interconnector Italia S.C.p.A. (the consortium comprising the parties selected pursuant to Law 99/2009), signed a Framework Agreement for transfer of the entire capital of Piemonte Savoia S.r.l., as well as the mandate for the realization, operation and maintenance of the private interconnector, operation valued at around 415 M €.

    The private portion of the financing for the work involves the participation of commercial and institutional banks. In particular, the European Investment Bank (EIB) has contributed to financing of the project with a €100 million loan and a further debt guarantee of €70 million.
  • Technical description

    The Italy - France connection is the only project of its type in the world given the technical and engineering solutions adopted: 190 km of HVDC cable (95 in Italy and 95 in France), invisibly routed — in part running underground and in part integrated into the existing motorway infrastructure — leaving the Val di Susa and Val Sangone in Italy and the Isère Valley in France intact, valleys that are quite similar, both in terms of their great beauty and their naturalistic and tourist value.

    Technically, the Piemonte-Savoie interconnection consists of two 320 kV DC lines, each with a maximum power of 600 MW, for a total of 1200 MW with bidirectional flow.  

    The Italy-France connection will be in direct current (HVDC High Voltage Direct Current); therefore, to connect it to the Italian and French alternating current power grids, two end-of-line conversion stations needed to be created. The conversion stations will be equipped with impressed-voltage VSC (Voltage Source Converter) technology.

    The substations will be built close to existing major electrical power nodes: the Piossasco power station in the province of Turin on the Italian side and the Grande Île station at Sainte Hélène du Lac in Savoie on the French side.


    Figure 4 - Illustration of the HVDC connection

    The connection consists of a double pair of cables with aluminium conductor and cross-linked polyethylene insulation. The cables will be inserted into underground polyethylene ducts running at a depth of about 170 cm or will be installed in the motorway viaducts, placed internally or externally depending on the type of viaduct, or placed beneath the flooring of existing tunnels, including the one Frejus tunnel being built (second line).

    On the Italian side, the route in part develops along the A32 motorway and in part runs along the state or provincial roads, with some stretches through agricultural land, as shown in the figure..


    Figure 5 - Route on the Italian side of the connection

    The Italian-French border will be crossed within the future Frejus tunnel (second line), under construction, covering a total length of about 13 km (approximately 6.5 of which is in Italy).


    Figure 6 - Border crossing (Frejus Tunnel)

    To maximise the environmental and territorial sustainability of the work, during the design stage, geological, morphological, morphological, flora, fauna and ecosystems studies were performed as were historical, archaeological and landscape studies.

    The project has been developed taking into account both the technical constraints and the need to minimise the pressure exerted on the territory by the works — hence the private ownership interest — preferring areas already affected by other infrastructures. In fact, the route has, as far as possible, been developed exploiting the existing roadway and motorway infrastructures. The result is an invisible work that leaves the surrounding territory unchanged.
  • Authorisation process

    The project — which has been part of the RTN development plans since 2008 — was authorized on 07 April 2011 for Italy with Measure 239/EL-177/141/2011 and on 18 June 2012 for the French side. Subsequently, as reported in the preceding paragraphs, the Italy-France Interconnector has been identified among the European Projects of Common Interest (PCI).

    According to a decree issued by the Ministry of Infrastructure and Transport, the above-mentioned authorization required that, at the existing tunnels in the motorway midway section between the municipalities of Bussoleno and Salbertrand, the electrical cables be housed inside new, specially dedicated ducts to be realized near the existing tunnels. This requirement posed several problems, not only of a technical nature; it also had significant repercussions on timing and cost of the works. Therefore, at the design stage, it was deemed necessary and advisable to modify the design of the section already authorized.

    This variant — which develops outside the A32 motorway (known as the “Media” section) — mainly falls along existing roadways, affecting the municipalities of Bussoleno, Susa, Gravere, Chiomonte, Exilles and Salbertrand, all located in the Province of Turin. Prior to submitting this modification for authorization, Terna implemented a participatory process with local authorities and information campaign for the general public.

    Therefore, a project was prepared for public participation and consultation, aimed at providing the broadest possible information on the variant to the project, which we shall describe in the next paragraph.

    At this stage of public consultation, Terna sent the request for approval of the variant to the relevant ministries.
    The procedure was concluded with authorization issued in a decree published on 05 August 2016 by MISE in concert with MIT and MATTM with Measure no. 239/EL-177/141/2011-VL.

    During the course of the technical design phase for the section for which Sitaf is not responsible, between the municipalities of Piossasco and Avigliana, and particularly in the section (approximately 200 m) that crosses the former quarry in the Municipality of Avigliana, in fulfilment of the requirements imposed by the Province of Turin regarding involvement in that section of provincial road SP 589, which has already been characterised by gravitational settlement in the past, it became necessary to produce a technical design that varied from what had been authorised: the route in that section had originally been planned to following provincial road SP 589 In fact, this design solution avoids interference with the monitoring instrumentation that is in place in the area (settlement gauges, inclinometers) and does not perform deep excavations which could alter the drainage/foundation mattress created by the Province to stabilise the landslide, which involves locating the cable duct, in the section in question, within the prefabricated box elements, each 1.50 m long, placed directly at ground level at an appropriate distance alongside the road.

    A request for authorization of this variant was made to the competent ministries on 26 May 2017. On 28 November 2017 MISE issued the authorisation for the location variant in the municipality of Avigliana (location Cava Sada). 
  • Description of the public consultation process for the project variant entitled “Middle Stretch” in the Municipalities of Bussoleno, Susa, Gravere, Chiomonte, Exilles and Salbertrand

    As mentioned in the previous paragraph, for the variant described above, which involved the Municipalities of Bussoleno, Susa, Gravere, Chiomonte, Exilles and Salbertrand, Terna drew up a plan of public consultation activities. Therefore, during 2015 Terna arranged participatory process meetings with all major municipal administrations involved and, at the same time, held 6 public meetings with the general public to present the details of the project and glean their observations. With the cooperation of the Municipalities, a communication program was established to keep the citizens of the concerned territories up-to-date.

    In particular, for the purpose of giving as much information as possible and enabling the widest public participation, on 25 May 2015 Terna held a press conference at the Municipality of Bussoleno, during which it announced the start of the activities provided for in the public consultation and information plan and the scheduling of 6 “Open Days” involving the Municipalities of Piedmont affected by the variant project, which were held according to this programme: 



    Date planned


    Council Chamber


    Municipality of Exilles

    Council Chamber



    Santa Caterina church



    Council Chamber



    Council Chamber



    Council Chamber


    The same day as the press conference, the dedicated webpage was published. This is accessible from the corporate website, and offers a non-technical summary, an information brochure and chorographies of the project and the terms were opened for sending via the dedicated e-mail address: Info-PiemonteSavoia, observations and queries related to the information and documents divulged during the entire consultation period.

    Terna informed the inhabitants of each Municipality involved in the Open Days with leaflets and posters affixed along the streets of the town centres and on specific municipal notice boards.


    Examples of leaflets put up in the notice boards of the Municipalities of Exilles and Susa.

    The meetings were held from 11:00 to 21:00 in the council chambers of the Municipalities affected by the work, with the exception of the Municipality of Chiomonte which made available Saint Catherine’s Church. In all these places (roll-up) information panels were put up, illustrating the various issues related to the location variant to the authorised “Italy-France” project. In detail: regional energy situation and reasons for the work, authorisation process and role of the Municipalities, planning and construction site elements, environmental and territorial aspects deriving from construction of the work.
    All participants were given a brochure which summarised the contents of the information panels. In addition, Terna technicians were at the disposal of all members of the public to provide information and clarifications and collect observations and suggestions.

    During the public consultation members of the public, associations and representatives of the Local Authorities formalised thirteen observations, for which the opportune counterarguments were provided.
    To these must be added the queries raised during the debates where the following requests were recorded most frequently:
    - Possible risks for health connected with electromagnetic fields;
    - Compatibility of laying the cable with the other services present on provincial highway 24;
    - Duration of the construction sites and difficulties caused by them;
    - Risks connected with the possible importation of nuclear energy;
    - Any benefits, in terms of lower energy costs, produced by construction of the work;
    - Possibility of rationalising existing power lines;
    - Assessment of alternative routes in the municipal territory of Chiomonte so as to avoid the state highway.

    These queries/observations/suggestions, raised in the ways indicated by Terna, were published on the web page dedicated to the variant, and the related answers to them were provided. To safeguard privacy the records were put online with no reference to the enquirer(s).
  • Description of the current state of progress for the Italian side (total public and private parts)

    The cable laying work on the Italian side started in March 2016, and to date has involved the Municipalities of Piossasco, Bruino, Sangano and Trana, with the completion of approximately 15 km of civil works and 13 km of cable ducts laid. The cable duct laying has mainly involved the existing roads, provincial roads SP6 and SP589, and some sections were constructed on unpaved roads and agricultural land.

    A significant point on the section that has been constructed is the Torrente Sangone stream crossing, completed in a trench under the river bed in the summer of 2016, with the partitioning of the water flow planned and achieved in close collaboration with the competent authorities.

    The construction sites for works in the Municipalities of Bussoleno, Susa and Exilles were started in August 2017.

    On 25 October 2017 the Ministry of Infrastructure and Transport (MIT) ruled to approve the agreement that entitles Terna to carry out the works and the crossing of the section of the A32 motorway managed by the Società Italiana per il Traforo Autostradale del Fréjus (SITAF).

    Following the Decree of Approval by MIT cited above, in the month of November 2017 construction sites pertaining to SITAF were opened.

    Work on the construction site for the Piossasco Conversion Station started in 2015, with the completion of preparatory works at the site. The activities for carrying out the main civil construction works of the season and the excavations of the foundations for the main buildings have now been completed. The works will proceed with the building of the foundation systems of the equipment inside the buildings and the installation of the electro-mechanical works

     The link is expected to be commissioned and enter into operation before 31 December 2019.

    Figure 7 – Schedule of works for cable link, Italy side

    Figure 8 – Schedule of works for Piossasco Conversion Station


    Figure 9 - Photographs of construction sites