Better electrical infrastructure will increase the profitability of offshore wind
Advances in electrical infrastructure are central to enabling the large-scale offshore wind farms that are necessary for the green shift. Electrical infrastructure can account for up to half of the total costs of offshore wind when the wind farms are established further from land and in deeper water than what is common today. New, improved electric power components are therefore necessary to reduce the costs of offshore wind. Increasing the transmission length and capacity of AC cables, for example, will reduce costs significantly.
The ongoing trend towards ever larger wind turbines requires the development of electric power components capable of functioning at ever higher voltage levels. This applies for instance to inter-array cables, connectors, transformer cables and export cables. The large variations in the production of wind power constitute another challenge, in that they lead to increased stress on the components.
These increased stresses affect reliability and require better condition monitoring and degradation models. Certain components are also sensitive to environmental stresses. This must be taken into account when constructing and placing the components. For example, transformer stations can be placed on the seabed, where there are no waves. Existing subsea technology from the oil and gas industry (such as transformers and connectors) can be used in wind farms, but costs must be reduced and performance improved.
Anther challenge related to the electrical infrastructure is the transition to more environmentally friendly materials. As an example, SINTEF is currently working on the development of lead-free subsea cable designs at higher voltage levels.
System integration of offshore wind farms is necessary for efficient operation
System integration of offshore wind farms is on the research agenda of the European transmission operators and wind farm developers. This includes but is not limited to system services, virtual power plants and interoperability.
Today, point-to-point connections (all offshore wind farms having their own, separate connection to shore) are used to connect offshore wind farms to the shoreside power grid. This will not work well for large-scale offshore wind development. It would result in a very large number of connections, and no economies of scale.
To bring the power ashore more efficiently (making offshore wind more profitable), we need a multinational offshore grid in the North Sea. Planning and operating such a grid poses technical challenges. Interactions between networks and components must be addressed in a context that includes several suppliers, which makes interoperability important. Furthermore, offshore wind farms must offer system services to support the transmission grid – energy storage and voltage and frequency control, for example. An optimisation framework should be established to coordinate these services and the power transmission with respect to grid needs, legal and market constraints, as well as the choice of energy carrier.
SINTEF is hard at work solving these and other challenges, for example in the NorthWind and Ocean Grid projects.
We work within these offshore wind areas:
- Electrothermal cable models
- Subsea substations
- New and improved component designs
- Models for degradation and lifetime assessment
- AC and DC based export systems
- New and environmentally friendly insulation materials
- System services
- Transient analyses and stability
- Configuration of the ocean grid
- Power electronics
Typical offshore wind assignments for us are:
- Analytical studies and numerical models
- Simulations
- Laboratory experiments
- Field measurements
Who are we doing this for?
- Energy companies and developers
- Suppliers and manufacturers
