German Offshore Energy Islands in the European Energy System - A case study analysis

The expansion of the political target to 70 GW of offshore wind in Germany compared to the old German grid development plan (NEP) will lead to an extreme increase in grid costs in order to integrate this higher amount of wind power into the German electricity market. For this reason, the task of this study is to examine the economic advantages and disadvantages of direct use of offshore electricity (e.g. through electromobility, heat pumps and new industrial processes) compared to hydrogen production with electricity from offshore wind.
The results show that Offshore Energy Islands (OEIs), taking into account meshing in the European North Sea grid and electrolyser flexibility, can contribute to the following aspects: Firstly, this results in savings in grid costs both for connecting offshore turbines to the coast and for inland routes. Secondly, they enable efficient hydrogen production without long transportation routes for the electricity. Thirdly, in times of low offshore wind and high solar PV generation, connecting the OEIs on the electricity side can make it possible to convert the surplus solar PV electricity into hydrogen. In this study, a scenario with two OEIs connected to the electricity grid results in annuity savings of 4 261 MEUR/yr, which is especially due to possible savings in HVDC cables.