The UK has been both the European leader, and world leader in the amount of offshore wind it has installed in its waters. The UK currently has an offshore wind installed capacity of approximately 10GW, with ambitions to reach an installed capacity of 40GW by 2030 as set out by Boris Johnson in the recent re-election campaign. This is a huge target for the UK, especially when compared to Europe, which aims to have an installed capacity of approximately 90GW by 2030 including the UKs 40GW (according to the 2030 National Energy and Climate Plans submitted in December 2019).
he UK has approached the development of offshore wind in a very different manner to the rest of the world. In the UK , it is the Wind Farm Developers (WFDs) responsibility to design, procure, and construct the transmission infrastructure required for the offshore wind farm. one built, the transmission assets are handed over to the Offshore Transmission Owner (OFTO).
This is very different to the approach carried out by other European countries where the National Transmission System Operator (TSO) is responsible for the development of the transmission asset. The image below shows the differences in approach to transmission in Europe.
Source: Ørsted
Over the past few years as the larger projects have started coming online, the cost difference between the developer led approach (UK) and the TSO led approach (Germany) have become apparent with clear differences in the cost of energy. A recent study conducted by DIW Econ found that the average Levelised Cost of Energy (LCoE) for transmission from the UK was around 16 EUR/MWh, whereas in Germany, it was approximately 35 EUR/MWh. Even after taking into account the differences in distance to shore, transmission technology used, and other factors, the cost difference between Germany and the UK was still 10 EUR/MWh.
This topic is being discussed here as it has come to the forefront again as transmission architecture in the offshore environment is under discussion in the UK. The UKs energy regulator Ofgem recently published their Decarbonisation Plan, where they indicated that a major change in the design of future UK offshore wind transmission will be required, with focus on shared transmission assets and the development of meshed grids. Ofgem declared in their report that the current arrangements for connecting offshore wind farms back into the national grid are not fit to support the ambitious UK target of 40GW by 2030, or any developments post 2030.
Ofgem specifically discussed that the continued use of radial links from wind farms back to land will not be economically, of publicly acceptable as the amount of offshore wind farms connecting back to land increases. Ofgem said it aims to work with National Grid to “explore whether a more coordinated offshore transmission system could reduce both financial and environmental costs”.
Ofgem also discussed planning for the development of meshed offshore grids allowing further interconnection between European national grids. the development of a meshed offshore grid is something which SuperNode has been promoting since its inception, and previously promoted by its founder Eddie O’Connor, who has been encouraging the adoption of a European SuperGrid for over a decade.
The report from Ofgem indicates that national bodies are now starting to come to the realisation that the development of an offshore grid is essential in Europes quest to install 450GW of offshore wind by 2050.