TenneT: Power Distribution in the North Sea

Future Project North Sea

The North Sea is the future of Northern Europe's electricity supply. Not only TenneT is convinced of thAT. “Given WindEurope’s forecasts  of the planned deployment of up to 70 GW offshore wind by 2030, new approaches must be investigated to connect large scale offshore wind to the onshore grids," explains TenneT CEO Mel Kroon.

The North Sea has ideal conditions for a large-scale expansion of offshore wind energy by the various riparian states. Basic prerequisite for this is that these countries cooperate in transporting electricity to where it is needed.

An Island as a Wind Power Hub

How exactly this can best be achieved is currently the subject of two different studies. The idea of building an island as a wind energy distribution hub (called 'Wind Power Hub') has been around for almost two years. Meanwhile, the list of companies interested in the project is getting longer and longer.

Now TenneT and German energy utility innogy have signed a Letter of Intent: In a joint study, the two partners intend to evaluate the opportunities and challenges of a cross-border distribution hub for offshore wind farms. To this end, feasible design options, the economic part and the regulatory and market requirements of such a combined and international infrastructure are to be examined first. The latest results of existing studies will also be incorporated.

This is what the Wind Power Hub in the North Sea could look like (Image: TenneT)

Cost Reductions as a Factor

At the same time, an outlook is to emerge on the effects of further cost reductions in offshore wind projects. Giles Dickson, CEO of the European Wind Energy Association WindEurope, recently pointed out at a conference that progressive technological change releases further savings potential.

Much is still possible in the field of HVDC connections alone. Advanced wind turbine converters, along with smarter HVDC converters, will be a key pillar to support system operations and maintain system security. According to Dickson, HVDC interconnectors already offer transmission system operators a high degree of flexibility. HDVC technology is now gearing up for multi-vendor, multi-connection wind farms that can be connected to two different onshore grids.

Converter station with HVDC connection in the North Sea (Image: TenneT)

To date, TenneT has implemented seven such HVDC and three HVAC offshore grid connections in Germany alone. Cooperating with innogy, who also have a lot of experience in offshore expansion, is a good fit. "A North Sea Wind Power Hub system supports the deployment of significantly larger volumes of offshore wind. The cooperation with innogy offers us a perfect opportunity to investigate such new approaches," says Kroon.

Hans Bünting, innogy Renewables CEO, agrees: “Research and development is crucial to bring renewable generation to the next level. Connecting offshore wind projects into an independent transmission system creates the potential to feed into multiple markets. The main benefit will be the ability to supply consumers with larger volumes of cheap, predictable and low carbon offshore wind power well into the future.”

WindConnector as an Alternative

Vattenfall also intends to further reduce the costs for offshore wind power. Operating a high-voltage cable between two planned offshore substations would allow e.g the British and Dutch electricity markets to be more closely linked. Due to the multiple use of transmission systems already planned, the additional investments are significantly lower than for a conventional connection line between the two countries.

This option will now also be examined more detailed, as TenneT and Vattenfall explained in a Memorandum of Understanding (MoU), forming the basis for cooperation in the preparation of the WindConnector study.

The WindConnector is to link Great Britain and the Netherlands (Image: TenneT)

Gunnar Groebler, Senior Vice President Wind Vattenfall, said: "Anything we can do to optimise our assets with a smart project like WindConnector is good for a competitive, low cost, fossil-free offshore wind industry and great news for consumers.”

Wilfried Breuer, Director Offshore at TenneT, emphasized that research in all directions is necessary to achieve optimal results: "In order to meet the climate targets of Paris, we must, among other things, move towards a development of wind at sea on a large scale. Scale size and at the same time affordability for society requires efficient, smart solutions and close cooperation at international level."