Our key tasks

We are primarily tasked with providing power transmission services, system services and facilitating the energy market. Our core tasks follow from our appointment as grid operator under the Dutch 'Elektriciteitswet' (E-wet) and the German 'Energiewirtschaftsgesetz' (EnWG).


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TenneT presents Hub and Spoke concept for large scale wind energy on the North Sea.

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Our grid

TenneT manages the high-voltage grid in the Netherlands and large parts of Germany. TenneT transmits electricity at 110,000 volts (110 kV) and higher. With over 22,500 kilometres of high-voltage lines, we cross borders and connect countries.

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Grid maps

Maps of our onshore and offshore high-voltage grid.

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Electricity market

The energy sector is developing rapidly. The process of European market integration began some years ago. Its purpose is to create a single European market that enables market parties to trade gas and electricity across national borders easily and efficiently.

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Transparency data

We provide transparency data on our operations on our Dutch and German transparency page and on ENTSO-E. 

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Our vision is to be one of the most transparent Transmission System Operators (TSO) in Europe and thereby creating value for society. In this Energy Insights section we present selected energy related topics and show data, information and valuable insights. 


Energy transition

Wind turbines and solar panels are the physical signs of consumers’ growing desire for clean, renewable energy.

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TenneT is a leading European electricity transmission system operator (TSO), with activities in the Netherlands and in Germany. We strive to ensure a reliable and uninterrupted supply of electricity in our high-voltage grid for some 41 million people.

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Direct current grid connection of wind farms in the eastern North Sea



  • 130 km long and 690 MW capacity
  • 45 km onshore cable
  • 85 km offshore cable

Grid connection point

  • converterstation Büttel Germany

Status of project

  • online since june 2015

About the project


The HelWin2 project includes the realisation of a 690 megawatt grid connection for wind farms near Helgoland. This is the third offshore grid connection in the eastern region of the North Sea. HelWin2 will initially connect the wind farm Amrumbank West. The direct current subsea cable route runs 85 kilometres from the offshore converter platform HelWin beta to the landing point at Büsum. From there, the land cable runs another 45 kilometres to the onshore converter station in Büttel.

In spring 2011, horizontal drillings were carried out beneath the Kiel Canal. Further boreholes for crossing underneath the land protection dyke took place in 2012. The underground cable and the subsea cables were laid in territorial waters in 2013. Furthermore, construction works for the onshore converter station in Büttel and the installation of the high-voltage technical equipment have been completed. .

In summer 2014, the offshore converter platform was erected and the subsea cable was laid.

The exterior steelwork for the topside of the offshore converter platform HelWin beta was completed in 2013. The installation work on the high-voltage technical platform equipment was completed in 2014. Then, in summer 2014, the offshore converter platform was erected and the deep-water subsea cable was laid.

The official commissioning of HelWin2 took place on 12 June 2015.

HelWin2 project

Online since 12th June in 2015.

Project downloads

Factsheet HelWin2 (german) (302 KB, pdf, 05/19/2016)

690 MW Gleichstrom-Netzanbindung für Windparks in der östlichen Nordsee

Category: Brochures
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Die Naturschutzprojekte von TenneT (german) (785 KB, pdf, 08/02/2016)

Aufwertung der Lebensräume von zahlreichen Pflanzen- und Tierarten

Category: Brochures
Die Naturschutzprojekte von TenneT (german) Download Download

Also interesting

TenneT Offshore brochure

"Energie von See an Land" brochure about TenneT offshore projects and technology (german only)

Offshore projects in Germany

Our other german offshore projects.

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Media footage

Your way to our pressfootage about HelWin2.

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