The project will facilitate the development of wind power projects totaling around 400 MW on Evia, the second largest of the Greek islands, by enabling the power they produce to be exported directly into the national power transmission grid.

The first link interconnects the Nea Makri substation on the coast of Attika with the Polypotamos substation on Evia and the second link interconnects the Kalamos substation, again on the coast of Attika, with the Amarynthos substation on Evia.

Assodivers was awarded by Nexans Norway AS the nearshore protection of two cables of 21km each and one cable of 9km. The 2-off 21km lengths were installed in parallel between the Nea Makri landfall on the mainland and the Polypotamos landfall on Evia. The 1-off 9km length was installed in parallel with 2-off existing submarine cables between the Kalamos landfall on the mainland and the Amarynthos landfall on Evia.

For the provision of the contracted services, Assodivers utilized the DP-capable 'FB Assodiver VII' as a working platform and towed to/from the workisites by TB 'Hydna'. The landfall cable protection works were succeded using 'AssoMultiTrencher' underwater trenching vehicle equipped with a cutting chain and cable depressor and operated from the support pontoon ‘Birbilo’. Post-burial works at transition zones were carried out by Assodiver’s diving personnel utilizing handheld inductors. At Polypotamos, where due to seabed inclination and hard substrate trenching could not be performed, the cables were protected by Cast Iron Shells (CIS) installed by Assodiver’s diving personnel. In addition, protection with Mix Concrete was applied in all four landfall areas in trenches from the shoreline up to 20m offshore. In particular at Polypotamos landfall area both land and sea trenches, excavated in rocky slope, were filled with cement to ensure cable protection at the splash zone and in shallow water.

Project Specifications

Attica-Evia / Nea Makri-Polypotamos

Year:
2013
Contractor:
Nexans Norway AS
Cable Type:
Power 3x170kV HVAC
Cable Weight:
75kg/m in air
Cable Diameter:
200mm
Service Provided:
Offshore Protection
Owner:
ADMIE
Trenching Length & Cover Depth:
7,637m @ 1.0m
Alternative Protection:
Mattresses: 80m CIS: 126m
Location:
Euboean Gulf, Greece
Max Water Depth:
85m