NordLink

NordLink is a high-voltage direct current (HVDC) interconnector project that links the power grids of Norway and Germany for the first time. The project was completed in 2020 can can be considered milestone in European energy integration.

Project Overview

The NordLink interconnector spans a total distance of 623 kilometers, making it Europe's longest HVDC connection when it was commissioned, although it was swiftly overtaken by Viking and North Sea Link. It consists of 516 kilometers of subsea cable, 54 kilometers of underground cable in Germany, and 53 kilometers of overhead line in Norway. The project connects Tonstad in Norway's Sirdal municipality to Wilster in the German state of Schleswig-Holstein.

Technical Specifications

NordLink operates at 525 kilovolts (kV) with a capacity of 1,400 megawatts (MW), enough to power approximately 3.6 million German households. The system employs a bi-pole configuration, utilizing two parallel mass-impregnated cables for the subsea portion. These cables have an outer diameter of 15 centimeters.

Converter Stations

The two converter stations are located in Wilster, Germany, and Tonstad, Norway. These stations use Voltage Sourced Converter (VSC) technology in the form of a cascaded 2-level converter from Hitachi.

Environmental Impact and Benefits

NordLink enables the exchange of surplus wind and solar power from Germany with hydroelectric power from Norway. This bidirectional flow of green energy helps balance supply and demand, enhancing energy security in both countries. The project is estimated to reduce annual carbon emissions by approximately one million tons.

Project Development and Stakeholders

The development of NordLink was a collaborative effort involving multiple stakeholders. The project was awarded in 2015 to a consortium comprising Statnett (Norway's state-run electricity transmission utility), TenneT (the Dutch state-run electricity transmission operator), and KfW (a German development bank). The total cost of the project was estimated between €1.5 billion and €2 billion.

Construction Challenges

The construction of NordLink presented unique challenges due to the diverse geographical conditions at each end of the interconnector. In Norway, the converter station was built in mountainous terrain with extremely hard ground, requiring extensive rock breaking. Conversely, the German site had soft, water-saturated soil that needed careful preparation to support the massive weight of the converter station.

Technological Innovations

NordLink claimed several technological firsts. It was the world's first VSC bi-pole installation to operate at 525 kV and 1,400 MW, nearly doubling the power transmission capacity of earlier systems. It was also briefly the world's longest VSC cable connector and the first interconnection between the Norwegian and German power grids.

Broader Impact on European Energy Market

The NordLink project contributes towards the integration of the European energy market. It allows for more efficient use of renewable energy resources across borders, contributing to price stabilization and increased energy security. The interconnector is recognized as a Project of Common Interest by the European Union, underlining its importance to the region's energy strategy.