Elering starts construction of Vaike Strait's 2nd sea cable

TALLINN - The construction work of the second sea cable of the Vaike Strait between the islands of Saaremaa and Muhu began on the order of Estonian transmission system operator (TSO) Elering this week.

Upon the completion of the cable, the dam between the islands will finally be freed from the approximately 60-year-old high-voltage overhead line.

The total length of the second 110-kilovolt sea cable in Vaike Strait is approximately seven kilometers, of which five kilometers are located directly in the sea. The cable connects the overhead line ending on the west coast of Muhu island with the Orissaare substation on Saaremaa island.

The work will be carried out by procurement winner Connecto Eesti. Excavation work for the pipeline on land will begin this week. In the first stage, excavation work will take place in Orissaare, and in the second stage on Muhu island, which will end approximately in May, after which the high-voltage cable will be installed in the pipeline. Excavation works will continue in the special conservation area of Vaike Strait from mid-July and the installation of the sea cable at the bottom of the strait is scheduled to take place in mid-August.

The diameter of the cable is 190 millimeters and the weight is 67 kilograms per meter. The cable will be installed in the sea as one long cable and sunk into the seabed to reduce the risk of damaging it. Along with the new cable, a fiber optic communication cable will also be installed. The new cable has the same technical characteristics as the first sea cable of the Vaike Strait installed in 2019. By October, the old high-voltage overhead line will be dismantled from the Vaike Strait dam, providing a safe flight path for birds moving over the dam.

The construction of the second sea cable is partially supported by the European Union's Recovery and Resilience Facility. The total cost of the establishment of the cable is 7.3 million euros.

Elering laid the first sea cable between Muhu and Saaremaa in 2019. This made it possible to dismantle one of the overhead lines from the masts of Vainatamm Causeway. At the same time, Elering equipped the remaining overhead line with markers, which made the line more visible to birds and thus improved safety.

Elering has additionally replaced the Soviet-era submarine cables in the Suur Vain Strait with modern ones -- the first one was completed in 2015, and the second in 2020. In total, Elering has invested 31.1 million euros in new submarine cables in the two straits.