This project creates knowledge to support the development of power grids offshore as well as onshore, against a backdrop of large-scale offshore wind development and a changing onshore energy system. To use Norway as an example, the government has announced plans to award areas for 30 GW offshore wind power by 2040. This implies an offshore power system with the same capacity as the existing Norwegian onshore power system. In other words, over the next decades, massive amounts of renewable energy from offshore wind need to be integrated into the Norwegian and European energy system. This should happen in a way that is economically efficient while at the same time ensuring security of electricity supply throughout the transition.
Read this popular science blog post from the project about an assessment of potential vulnerabilities in this future power system that might threaten the security of supply: When sea meets land: New vulnerabilities in the power system?
From single cables to coupled offshore grids
Until now, offshore grid development has been restricted to single interconnectors and cables to/from shore for offshore wind farms or oil and gas platforms. With more offshore wind, more varied and complex offshore grids are expected, with several interconnected sub-grids with interconnections with the onshore power grid of several countries. We do not know what the grid will look like in the future, but the building blocks of a future coupled offshore and onshore grid are being developed right now. These “building blocks” include methods and models for assessing possible solutions and development pathways for the power system. To achieve this, we must consider both the power systems and their components and collaborate across the value chain – from component and technology suppliers to power system planners and operators. Therefore, in this project SINTEF and NTNU have joined forces with Statnett, Aker Solutions and GE Vernova.
Methods and models for the future power system
The project has since its kick-off in 2024 been establishing the necessary data basis and modelling assumptions to simulate the operation of a future power system with a large share of production from offshore wind. This is necessary to analyse and optimize solutions and strategies for how the system should develop. The project has prepared a data set for the Nordic power system that is based on open sources and that therefore can be published openly. The work with the data set is done in collaboration with the EU-funded project WILLOW, where SINTEF also contributes, and when shared openly it can be of value for yet more research projects.
Operational models and system security
Models for how the system will be operated need to be relatively simple to be able to cover a long-term grid planning horizon stretching decades into the future. The models should nevertheless be able to capture a key feature of how the system is operated: By limiting the flow across given power lines, operators ensure that there is sufficient reserve capacity in the grid in case of outages of any of the power lines. Operational models that can account for this are called security-constrained optimal power flow (SCOPF) models. The project has investigated different SCOPF models that can handle offshore grids based on high-voltage direct current technology (HVDC) as well as existing onshore grids based on alternating current (HVAC) technology. Such models are necessary to evaluate grid solutions for coupled offshore and onshore grids and will be building blocks for the tools that system operators will be using in the future. Research code for SCOPF models are under development in the project and will be made available as open-source code.
Vulnerabilities and resilience
The power system must be designed and developed in a manner that ensures security of supply. As some of the design choices are being made already now, we must ensure that we are not introducing new vulnerabilities into the power system but makes it robust and resilient to failures. The project has therefore carried out an analysis of potential vulnerabilities in future coupled offshore and onshore power grids. This work was carried out in collaboration with the EU-funded project MISSION, where SINTEF is investigating new HVAC and HVDC switchgear. The vulnerability analysis was presented at the international CIGRE symposium that was organized in Trondheim in May 2025.
Socio-economic perspective
For grid developers, the guiding principle and a major challenge is to understand which solutions are socio-economically favourable. Cost-benefit analyses should account for socio-economic impacts such as investment costs, security of supply, the value of new power production, and more. Grid development strategies should also be robust and flexible with respect to uncertainties in future needs (so called real options). An additional challenge with offshore grids is to put a value on new benefits of HVDC technology. The project has started reviewing the practice among system operators for cost-benefit analysis of coupled offshore and onshore power grids and comparing it with methods available in the research literature. The aim is to reach a better understanding of socio-economic profitability (e.g., of HVDC investments) and to provide inputs to processes and strategies for grid development.