Crete - Attica
Island LinkOperationalGR1,000 MW500 kV368 km2025
Also known as:Attica–Crete HVDC Interconnection, Crete–Attica Electrical Interconnection, Ariadne Interconnection, HVDC Crete-Attica interconnection 2×500 MW – 1st stage, ARIADNE ATTICA CRETE INTERCONNECTION, Electric Interconnection of Crete-Attica Ariadne, Crete–Attica interconnection
Status:Operational
Capacity:1,000 MW
Project Company:
ARIADNE INTERCONNECTION S.P.S.A.
Type:island link
Website:www.ariadne-interconnection.gr
The Crete–Attica electrical interconnection (Ariadne Interconnection) is a 1,000 MW (2×500 MW) bipolar HVDC link that integrates the island of Crete with mainland Greece (Attica). Built and developed by IPTO/ADMIE through the special-purpose vehicle Ariadne Interconnection, the project uses ±500 kV Voltage Source Converter (VSC) technology and comprises two subsea...
Supply Chain (5)
Project Timeline (18)
25 Jun 2025System Testing
On 25 June 2025, IPTO announced that the Crete–Attica HVDC submarine interconnection had successfully transferred 320 MW of electric power from Crete to Attica via the Ariadne Interconnection, demonstrating the link’s capability for bidirectional energy flows under real operating conditions while ongoing tests aim to reach maximum transmission capacity per cable.
24 May 2025First Power
On 24 May 2025, the Crete–Attica HVDC interconnector transmitted direct current electricity between Crete and mainland Greece for the first time, marking the start of trial operation. Following converter station energisation on 21 May 2025, IPTO’s subsidiary Ariadne Interconnection began sending power across the 1 GW, ±500 kV subsea link, with trial operations scheduled to continue through the summer to progressively test bidirectional power flows and ramp toward full capacity.
24 May 2025Commercial Operations Full Power
The Attica–Crete interconnector was officially placed in operation and fully commissioned on 24 May 2025, integrating Crete into the Greek national power grid via a 500 kV, 1 GW HVDC link. Developed by IPTO subsidiary Ariadne Interconnection with one 500 MW subsea cable system supplied by Nexans and the other by Prysmian, the project entered operational service on this date, after which trial operation continued through the summer for further performance verification.
2025Other Permit Awarded
Licence: Environmental permit / approval of environmental conditions (AEPO) for the 150 kV Chania–Damasta transmission line
An environmental permit (approval of environmental conditions, AEPO) was granted for the new 150 kV Chania–Damasta transmission line in western Crete, a supporting asset essential for the optimal combined use and simultaneous operation of Crete’s two interconnections with mainland Greece (Attica and Peloponnese). This permit approval enables construction and operation of the line, which will strengthen the Cretan transmission network linked to the Crete–Attica HVDC interconnector.
2025Onss Commissioned
By early 2025, intensive equipment tests on the Crete–Attica HVDC link had enabled the new 150 kV Damasta substation in Crete to be successfully connected to the island’s AC grid, confirming commissioning of this onshore substation. At the same time, the 500 kV underground and subsea cables between the Attica and Crete converter stations were fully tested, preparing the interconnector for subsequent energisation and trial operation.
17 Jul 2024Capital Support Awarded
On 17 July 2024, Greece’s Ministry of Economy and Finance decided to include the second stage of the Crete–Attica interconnection in the NSRF 2021–2027 Operational Programme "Environment and Climate Change", approving funding of up to €222.3 million as part of total EU co‑financing for the project that can reach €535.5 million.
€222.3M (grant)
16 Feb 2024Cable Installation Complete
As reported in February 2024, the underground section of the Crete–Attica electricity interconnection between mainland Greece and Crete had been completed, allowing project activities to shift focus to constructing the converter stations at Damasta in Crete and Koumoundouros in Attica.
31 Dec 2023Capital Support Awarded
By 31 December 2023, the first stage of the Crete–Attica electrical interconnection (Phase II of Crete’s connection to the Hellenic grid) had been funded with €300.2 million from Greece’s NSRF 2014–2020 Operational Programme "Infrastructure, Environment and Sustainable Development", including an ERDF contribution of €250.6 million confirmed by the European Commission.
€300.2M (grant)
2023Cable Installation Complete
By 2023, Nexans had completed design, manufacturing, subsea installation and Site Acceptance Testing for its 500 MW, 500 kV HVDC subsea cable system forming half of the 1,000 MW Crete–Attica bipole interconnection between Attica and the Heraklion area of Crete.
2021Capital Support Awarded
In 2021, Ariadne Interconnection and the European Investment Bank signed a €200 million, 20‑year loan agreement (with a €100 million extension option) for the Crete–Attica interconnection, guaranteed by the Greek state, making EIB an equal co‑financier alongside Eurobank and strengthening the project’s financing terms.
€200M (debt)