Transnational Interconnector case studies



The NorthConnect interconnector will have a capacity of 1400 MW, will be 655 km in length and is intended to facilitate the trading of energy with Norway and continental Europe. The interconnector will be routed from Simadalen in Norway, across the North Sea to Long Haven Bay, Peterhead in Scotland.

Norwegian electricity is primarily produced from hydro-electric sources, while Scotland has an increasing proportion of wind power in their energy mix. This interconnector will connect two complementary and previously disconnected power systems, helping both to balance the grid between two countries, encourage international cooperation and allow wider trading across Europe. NorthConnect are aiming for the cable to be operational in 2022.


Figure 11. NorthConnect cable route from Scotland to Norway

In 2013 the NorthConnect scheme was designated as a “Project of Common Interest” or PCI, within the legal framework of the European Union and European Economic Area, of which Norway is also a signatory state. This means that NorthConnect is seen as an important project for achieving Europe’s energy market and climate change targets.  As a result it has been included in the 2014 Ten Year Network Development Plan (TYNDP) for European electricity projects, and is also included on the 2015 list of PCI projects.


Planning and licensing

Differences exist between Scotland’s and Norway’s planning and licensing procedure and there is no coherence. For example, Norway has 1 consent which covers both onshore and offshore planning whereas Scotland has 2 consents (1 for onshore and 1 for offshore). There are also differences in the timings of the planning and licensing process and in particular for the EIA process where Norway completes their EIA process at the beginning of the planning process compared to further on in the process in Scotland. It was suggested that Norway finds Scotland’s planning process very onerous and long, however in comparison, Norway’s process may be shorter but suggested to be less clear. 

Four potential offshore cable corridors were considered initially and the routes were visualised and mapped in GIS. Data from Scotland’s NMPi database and Norway’s equivalent database was used. Environmental constraint mapping, technical constraints, safety constraints and economic viability was considered. The following aspects were taken into consideration in the analysis:

  • Physical characteristics of the cable; 
  • Existing infrastructure including pipelines, cables, and offshore installations – excluded from the survey corridor by at least 500 m. Preference for NorthConnect cables to cross existing cables and pipelines at approximately 90 degrees, as opposed to obliquely
  • Bathymetry; 
  • Seabed geology and sediment characteristics – areas of hard sediment types were excluded from the survey corridor where possible
  • Commercial fisheries, shipping and navigation; 
  • Cultural heritage and marine archaeology - wrecks
  • Benthic ecology and habitat types; and 
  • Designated sites and protected habitats.

The final cable route design has yet to be determined but the outputs of the survey will also aid in the identification of offshore cable protection requirements and appropriate installation technique selection.  NorthConnect will also carry out an EIA and produce an Environmental Statement to support the planning and marine licensing applications for the cable. 

To help mitigate some of the spatial implications, the cables will be buried to a depth of 1.5 meters to avoid snagging with fishing vessel gear, EMF impacts to elasmobranchs and diadromous fish and other magnetic field and compass deviations. The cables will also be bundled into the same trench to reduce development time and environmental impacts. In Scotland, there are no Government-led determined spatial or technical planning criteria – the 250 meter buffer zone at either side of the cable is a rule of thumb set by industry but it is not a technical restriction. Routing decisions are made by the developer and are based on risks to the cable and then approved through the marine licensing process. 

The proposed NorthConnect cable route will cross other cables and pipelines in the North Sea and therefore they will follow the International Cable Protection Committee (ICPC) recommendation (No. 3, Issue: 10A) for cable and pipeline crossings (International Cable Protection Committee, 2017).  The crossings shall be treated individually during detailed design considering aspects such as regional constraints, requirements from the crossed infrastructure owner, practicalities regarding trenching near the crossing, volume of rock ramps, stability and top cover. The angle between the NorthConnect HVDC cables and the crossed utility shall be as close to 90 degrees as practicable and not be less than 45 degrees for a distance of minimum 200 m from the crossed asset.


Spatial implications

Due to the scale of the development and its proximity to designated areas there is potential for the NorthConnect interconnector to have an effect on the environment. The spatial considerations for each country are quite different due to different geophysical environments. For example, on the Norwegian side, there are unique Norwegian fjords which are very deep (around 800 meters depth) which gives significant technical challenges for cable routing. Underwater rock falls are also common in the fords which can damage the cables. The fjords are also very congested with cables, particularly telecommunication cables which tend to be free-hanging because it is too expensive and difficult to trench them. The location of these free-hanging cables is also poorly recorded and largely unknown, giving routing and navigation issues. Also on the Norwegian side, there are lots of aquaculture farms surrounding the nearshore areas which need to be avoided. 

On the Scottish side, the inshore area of the cable route is important commercial fishing grounds including creelers, scallop dredgers and trawling. However a good relationship has been built with the fishing industry and spatial implications are being resolved. 

There are also onshore spatial implications which are important to link up the offshore infrastructure. The main issue is locating an appropriate location for the converter station which requires a large space and also locating grid connection points. On Scotland’s east coast, there are only two main sites to physically connect to the grid, Peterhead and Cockenzie. However Peterhead is already over capacity and Cockenzie is a challenging location. This means there is a substantial limit on grid strong points. 



The lifespan of the project is 40 years and the decommissioning plan will be fully developed prior to decommissioning. The likely approach, at a strategic level, will be to remove cables where economically viable, environmentally acceptable and practicable to do so.  Due to the value of the metals in the cables it is highly likely that it will be economically viable to remove the cables to allow them to be recycled.  Ecological surveys may be required to ensure it is environmentally acceptable, as there is a potential that over 40 years the habitats will have changed and protected habitats or species may have colonised the area.


How MSP can contribute to better cable planning

As suggestions from NorthConnect, MSP can contribute to better cable planning by providing open-access information and data relevant to cable development to allow developers to make good routing decisions. It can also help by identifying more locations for converter stations and onshore connections to the grid. 


COBRA cable


The COBRA cable is a 700 MW capacity interconnector between the Netherlands and Denmark. This PCI will have a length of around 325 kilometers between Eemshaven (the Netherlands) and Endrup (Denmark). Figure 12shows the schematic route of the COBRA cable. It starts in the Netherlands with an existing electricity grid and is connected with a high-voltage substation and converter station. At this stage the cable is a HVAC but then the converter station transforms the electricity from HVAC to HVDC. The electricity comes from the Netherlands to Denmark or vice versa and passes through German territorial waters and the German EEZ. In Denmark there is another converter station, which transforms the electricity from HVDC to HVAC. 

This interconnector will benefit both countries as for example Denmark’s wind energy can be imported to the Netherlands and there will be an increased energy security. There are also future plans to connect an offshore windfarm with this interconnector. However this may pose some regulatory challenges. Overall, this interconnector will help to meet a key target of the EU, the realization of a sustainable international energy market. It is expected to be commissioned in early 2019.



Figure 12. Overview of COBRA cable. Source:

Planning and licensing

In the German EEZ of the North Sea the project started the approval procedure for the area of responsibility of the Federal Maritime and Hydrographic Agency in 2010 with siting and routing studies. Following this was the first consultation with stakeholders and the public. In 2012 the project sponsor paused the licensing procedure till 2014. When the project started back up, screening and scoping took place as well as some surveys and an EIA. The permit application was then prepared and consulted upon by the public and stakeholders. After a determination period, the permits were granted and a comprehensive decision was received, with this the final investment was decided. Construction then began in 2016. 

As this interconnector is routed through three different countries, different key consents and permissions are required. For the Netherlands the key consents and permissions are: marine licence, Nature protection Licence, Exemption from the Species Protection Act (TBC), Seabed Survey Permit (TBC) and a partly EIA. The following permissions are required in the German EEZ: Seabed Survey licence, Mining law (LBEG) and Mining law (BSH), the latter follows the LBEG permit. The following permissions are granted by BSH for the German EEZ: EIA, shipping, fishing and offshore windfarms. In Denmark, consent includes 4 permits (DEA)4a Offshore permit for installation of marine cable (DEA)4b Seabed Survey license (DEA)Local planning permissions for onshore competent – municipalitiesand an EIA Permit for onshore component. This process runs parallel with the 4a (DNA).

For the German EEZ, BSH sent the application to all relevant stakeholders and asked for statements or comments, of which the developer had the chance to respond to. In the process different routing options were analysed, with consideration of the impact for different uses and sectors: shipping, airspace, fisheries, environment with flora and fauna as well animals, cables and pipelines, research, pollution of the sea, security, cultural goods, offshore windfarms and tourism.


Spatial implications

The transnational route of this cable will lead the cable through different territorial waters and EEZ’s which is likely to cause spatial implications, however the cable will have to follow the respective principles and regulations of each country. Marine sectors in all countries will also have the opportunity to raise their concerns about the planned routing and how it might impact them.