Elering has invested 30 million euros in the security of supply of Estonian islands

The constructors will deliver and Elering will receive the second modern 110 kV submarine cable today on Muhu Island which was installed in the Suur Väin Strait this summer. Along with this project, the company has invested approximately 30 million euros in the security of supply of the islands in the 2015-2020 period.

Improving the security of supply for electricity consumers on the islands has been one of the major priorities for Elering in the last few years. Since 2015, the most important projects have included installing two new submarine cables in the Suur Väin Strait, as well as a modern submarine cable in the Väike Väin Strait. Võiküla, Leisi and Orissaare substations have all been upgraded.

In addition to the second submarine cable installed in the Suur Väin Strait in the summer, the reorganisation work of the overhead transmission line on the Väinatamm Causeway was finished this autumn, resulting in the decrease of the overhead cables at the location by a half. In the course of the reorganisation work on the Väinatamm Causeway, more than 2,100 overhead wire markers were installed, which render the overhead lines more visible to birds and therefore safer.

In the next few years, Elering will renovate, within the programme of the security of supply of the islands, Muhu substation and Sikassaare substation next to Kuressaare, and also place the two overhead transmission lines over Muhu Island onto separate masts, which is the last stage of creating an electricity connection consisting of two independent lines from the mainland to Kuressaare.

The capacity of the submarine cable installed in the Suur Väin Strait this year is 520 amperes, its dimension is 190 mm, and it weighs 67 kg per metre. The cable was installed in the sea in one single part, without extension couplings. The cable was embedded in the seabed at a depth of 1-1.5 metres in order to reduce the risk of any damage to it, and a fibre-optic communications cable was installed in the sea along with the new cable.

Elering entered into a contract in 2018 with Merko Infra and Connecto Eesti in order to build the received submarine cable. The cable was manufactured in Prysmian’s factory in Finland. Building the submarine cable cost around nine million euros.

Before the construction of the new 110 kV submarine cables, there were a total of six 35 kV submarine cables in the Suur Väin Strait. As of now, thanks to the completion of the new cables, Elering has removed three Soviet-era depreciated cables from the sea. The removal of the remaining three old cables from the sea is also scheduled in the subsequent years. The modern submarine cables are more environmentally friendly compared to the old cables as they use polyethylene insulation instead of paper impregnated in oil.