The strong growth of offshore wind energy requires an expansion of the electricity grid. TNO is investigating combinations of the grid connection with international electricity transport and local energy conversion, for example to hydrogen, leading to lower costs, higher reliability and flexibility and thus to a higher market value. TNO is also conducting research into improving the voltage quality and reliability of cables.

Offshore grid

The North Sea countries are committed to strong growth of offshore wind energy, which requires an expansion of the offshore and onshore electricity grid. The larger size of the wind farms and their greater distance from the onshore grid pose technical and economic challenges. Recent studies have shown that coordinated development of the offshore grid offers cost advantages over individual connections and is also technically feasible. TNO has gained knowledge from this for and integrated analysis of scenarios for offshore grids for wind farm developers, governments and grid operators.

Harmonic filter at high voltage station (source: TenneT)

Voltage quality

The grid operator has high demands on large generation units such as offshore wind farms, partly in order to guarantee the voltage quality. The wind turbines are connected via power electronic converters and long undersea cables, which can lead to unwanted harmonic voltages and currents. In collaboration with stakeholders and knowledge partners, TNO is researching improved design procedures to limit these harmonics in order to realise cost benefits and higher reliability.


When the limits of fully electrical connection of offshore wind farms are reached in the long run, conversion to hydrogen via electrolysis is a promising option. Hydrogen as an energy carrier offers cost advantages for transporting large capacities over long distances and can provide the necessary flexibility in the energy supply as a storage buffer. In addition, hydrogen can be used in many ways, particularly as a raw material and energy source for the process industry and for heavy transport. At the TNO Wind Turbine Test Field in the Wieringer lake, a wind turbine developed by Lagerwey will be tested in 2019 with a linked conversion to hydrogen.

Cable reliability

TNO is co-initiator of a consortium with 20 industry and R&D partners that is working on improving the reliability of undersea cables. TNO is involved in the optimisation of installation and maintenance and in the development of continuous monitoring of mechanical integrity. If you are interested in participating, please contact Edwin Wiggelinkhuizen.


Less production, higher yield

TNO is conducting research in order to be able to produce and transport wind energy more cheaply. Innovative electrical infrastructure and the integrated design, installation and control of medium and... Read more

Towards large-scale generation of wind energy

The Dutch government has agreed with the energy sector that the near future will already see that energy generated from sustainable sources will be a substantial share of the energy mix. The future Dutch energy... Read more

From grey and blue to green hydrogen

Production from water via electrolysis with sustainable electricity from sun and wind is a CO2-free alternative. But for the production of green hydrogen, there are still technological barriers to be... Read more

Edwin Jan Wiggelinkhuizen, MSc

  • Wind Energy Technology