Landsnet, the Icelandic TSO (Transmission System Operator), maintains and operates the transmission system in Iceland. The system is isolated from other transmission systems, supplying electric power to the Icelandic society. Total length of the transmission lines is approximately 3600 km on three voltage levels (66 kV, 132 kV and 220 kV). Around 80% of the electric energy generated is consumed by power intensive customers (aluminium smelters, ferrosilicium plants and data centers). The generated energy is entirely renewable, 75% hydro based and 25% utilising geothermal power, with a total installed capacity of approximately 2.8 GW. The peak load is around 2.5 GW.

The transmission system is characterised by relatively low short-circuit capacity and two centres of inertia; one in the Northeast and the other in Southwest, connected together by weak and relatively long 132 kV lines along the shoreline. Landsnet is now working on upgrading the connection between the areas and is facing challenges due to upcoming large-scale wind power projects. There are plans and ideas (in various stages) for more than 3 GW of installed wind capacity alone in Iceland.

In that context, Landsnet initiated a research project for assessing how to manage this challenge. The project is twofold; Phase I focuses on what we should and can do and Phase II on how to do it.

The goal of the project is to provide a roadmap towards a „target grid“ for 2050+, thus giving quite valuable guidance to the system planning process at Landsnet. The project will, as well, provide guidance for a safe and firm integration of wind power into an isolated and weak transmission grid and highlight the necessary requirements for feasibility studies. The necessity of involving TSOs in the process of selecting locations for wind integration and large consumers (e.g. electrolysers) will be emphasized and justified.In Phase I we have developed a tool for assessing the impact of wind variability on the transmission system. The tool uses simplified grid model to evaluate how changes in wind generation between adjacent time intervals affect the transmission system. It processes long time series of wind data, converts them into power generation series, and determines the distribution of the power flow variations across grid branches in the system. This allows identification of stress points, assessment of variability impacts on individual lines and transformers, and provides a statistical and visual basis for planning mitigation measures. The results from Phase I will give us important foundation for how to move on, e.g. about the need (and location) for reserves as well as grid enhancements.

Phase II is the main system modelling and simulation part of the project. Based on the results from Phase I, wind integration scenarios will be defined and possible grid solutions modelled and simulated. The solutions will comprise grid enhancements (new grid components and reinforcements, increased meshing), new technology (STATCOMs, synchrocondensers, storage, grid-forming converters etc.), market solutions (e.g. flexible consumption) etc.