A consortium led by Siemens Gas and Power (Siemens Energy) has been awarded a turnkey contract for two converter stations for the Greek high-voltage direct-current (HVDC) link that will connect Crete, Greece's largest and most populous island, with the mainland of Greece. The project will enable an exchange of electricity of up to 1000 MW to enhance reliability of power supply and facilitate integration of renewable energy sources in the power grid.
The customer is Ariadne Interconnection S.P.S.A., a wholly owned entity of Greek Independent Power Transmission Operator (IPTO). Commissioning of the interconnector is scheduled for mid 2023. Total order volume for the consortium is 370 million euros (US$418.5 million).
Siemens will cooperate in the consortium with Terna S.A., a construction company in Greece. The engineering, procurement, and construction (EPC) turnkey contract comprises design, supply, and installation of a 1000-MW converter system at a dc voltage of ±500 kV, a gas-insulated switchgear (GIS) substation on Crete, including 10-year service contracts for the GIS and control and protection systems of both the HVDC stations.
The two converter stations — one located in the Attica region near Athens and the other near Damasta in the north of Crete — will be linked by a 330-km long dc power cable. Terna will be responsible for the HV distribution systems, the entire civil works, and the erection of all equipment of the HVDC project.
Both converter stations will use HVDC Plus voltage-sourced converters in a modular multilevel converter arrangement (VSC-MMC) that converts ac to dc back to ac on the other side of the link. The system combines the advantages of HVDC transmission with benefits like ac voltage control, black start capability, minimized power transmission losses, grid stabilization, and high availability.
Currently, Crete's energy supply mainly relies on outdated fossil-fueled power plants, which will be shut down by the end of 2022. The interconnector will facilitate the transmission of energy from renewable resources generated on the Greek mainland to the island. It is, therefore, expected to reduce carbon emissions by 500,000 tons in its first full year of operation.
"The Attica-Crete interconnector is another example of the added-value that Siemens Energy can offer customers to advance the global energy transition. I'm very proud that our proven state-of-the-art HVDC technology will enable an increased integration of renewable energy, reduce reliance on fossil fuel, and enhance grid security," said Beatrix Natter, CEO of the transmission division at Siemens Energy.