/  May 01, 2018  -  April 30, 2022

NSON II: North Seas Offshore Network II

University Kassel, Leibniz University Hannover, TenneT TSO GmbH
Funding BMWK (Federal Ministry for Economic Affairs and Climate Action)
Duration 01.01.2020 - 31.12.2022
Scientists Denis Mende, Yannic Harms, David Sebastian Stock, Philipp Härtel, Felix Frischmuth, Manuel Valois, Lothar Löwer



Project Goal

The overall objective of the NSON II project is to develop new technically and economically efficient ways of connecting offshore systems in the short and medium term. The focus of the project is on the facilities and projects in the German Bight.

In this context, the project addresses scientific questions concerning the control, operational management and planning of such systems. For short- and medium-term questions, the project is divided into the main research areas of "plant and system control" and "optimized grid planning and operation of offshore systems". For long-term questions regarding the development in the offshore sector and for the handling of the complex mathematical problems that arise in all dimensions, the project is rounded off by the two further focal points of investigation "Robust market-based scenario planning under uncertainty" and "Mathematical methods and procedures". The graph at the bottom of the page shows the key points of the study.

The main points give lead to different research questions for the project. These are listed below:


Focus "Turbine and power plant controller":

  • What requirements exist with regard to the control of HVDC converter stations in offshore grids with three-phase interconnection?
  • To what extent are the developed control concepts suitable for a extensive power flow optimization across multiple control areas within the framework of an controlled interconnected system?
  • Which control concepts and operation management strategies are necessary for the AC-side parallel and meshed operation of different HVDC technologies and which technical possibilities and limits result from such an operation?
  • What is the necessary (information) exchange that arises between the different stakeholders within an interconnected area (coupled via an HVDC system in the North Sea), especially with regard to system operation and the provision of ancillary services?


Focus "Optimized grid planning and operation of offshore systems":

  • What actions and operating strategies are required to exploit the potential of the HVDC offshore grid and offshore wind turbines (WTG) and how are these to be evaluated in technical and economic terms?
  • What are the grid-side requirements that arise with regard to grid operation as well as grid planning, especially of HVDC-coupled grid areas?


Focus "Robust market-based scenario planning under uncertainty":

  • How can uncertainties and correlations be taken into account in investment and planning models in order to make robust grid expansion decisions (especially in long-term scenarios with a high degree of decarbonization)?
  • How can these be efficiently handled (parallelized) in mathematical optimization models and solving procedures?
  • To what extent can and must technical and economic issues be modelled and answered together, especially in the subject areas of grid expansion and market-driven exchange services between market areas?
  • How can the progressively increasing amount of offshore wind generation be connected in a cost-efficient manner through the use of new concepts (esp. parallel operation)?
  • What type of economies of scale can be implemented in order to boost the connection of new offshore projects?


Focus "Mathematical methods and procedures"

  • How can time series-based optimization models be aggregated so that essential dynamic problem aspects can be described sufficiently accurately and the resulting models can be solved fast enough?
  • How can reliability requirements be suitably described mathematically and efficiently integrated into network planning, operation and power flow models in a way that can be solved?