Subsea interconnectors have made sharing renewable energy across seas a tangible reality. A lot has changed since 1954 when the first submarine HVDC interconnector cable was installed, connecting Gotland Island to the Swedish Mainland. Now there is a pipeline of projects planned globally in the magnitude of 12,000MW by 2025. The North Sea region in Europe is seeing maximum activity in this area owing to the renewable energy surplus experienced by the countries in this region. In fact, offshore resources could cover 15% of regional demand for the countries in this region.
The Interconnectors that matter for Europe
For the North Sea Link, the connection will be made via subsea cables. Credit: North Sea Link website
North Sea Link (NSL), linking the UK with Norway, currently is the longest interconnector in the world at 724 KM (450mi). The NSL harnesses Norway’s hydropower and the UK’s wind energy and costs around €1.6 billion ($1.86 billion). This joint venture between Britain’s National Grid and Norway’s Statnett recently started operations. It has taken six years to build, and it hopes to reach its 1.4GW full capacity in a three-month span.
1.4 GW Viking Link, on completion, will stretch 760 km between the UK and Denmark. The project is a joint venture signed between the National Grid and Energinet and would be completed by 2023. Nordic Investment Bank recently signed a 10-year loan to the tune of €1.34million with the Danish TSO Energinet. They pegged the total project cost at €2billion. Both the NSL and the Viking Link have prevented over 1.6 million tonnes of carbon emissions, according to the National Grid.
Longest HVDC interconnector links in Europe
At 1,400MW, the NordLink covers 623 km (387-mil) and runs between Norway and Germany. This joint partnership between Norwegian TSO Statnett and the Dutch TSO TenneT started operations this year (2021). The submarine interconnector will ensure reliable energy transmission between the countries for 40 years and provide climate-neutral energy for some 3.6 million households. The estimated total costs for NordLink is in the cost range of €1.7 – 1.8 billion.
NorNed Cable, which extends 580-kilometre (360 mi) between Norway and Netherlands, was once the longest submarine power cable in the world. It took €600m to get this bipolar HVDC link operational. A joint project of Statnett and its Dutch counterpart TenneT, it has two converter stations produced by ABB. When the cable started operations back in 2009, it generated annual revenues of approximately €64 million.
COBRAcable (COpenhagen-BRussels-Amsterdam cable) with a capacity of 700 MW connects the Netherlands and the Denmark regions. Owned by Energinet.dk and TenneT, it has an annual transmission capacity of 6.1 TWh. Denmark and the Netherlands have also exchanged electricity since 2019 via the COBRAcable, which runs a length of 325 kilometres. The construction cost ran up to €580m, and it has a capacity that can power 700,000 households.
The EuroAsia and EuroAfrica interconnectors are some of the notable projects lined up. Greece and Egypt are looking at laying a 2 GW 1,707 KM submarine interconnector across the Mediterranean Sea. Cyprus, Greece, and Israel have also signed a memorandum of understanding to construct the first EuroAsia Interconnector that would be 1500 KM and could cost €760 million.
The NorthConnect or the Scotland–Norway interconnector is another proposed 650 km (400-mile) 1,400 MW HVDC interconnector in the North Sea region. Owned by four public power companies (Agder Energi, E-CO, Lyse Energi, Vattenfall) and is budgeted for around £1.75 billion.
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