Abstract
AECOM was commissioned by The Crown Estate, in partnership with National Grid Electricity Transmission, National Grid Electricity System Operator and the Marine Management Organisation to consider the influence of spatial constraints on approaches to the connection of future offshore wind farms to the electricity transmission system along the east coast of England from the Humber Estuary in the north to Thames Estuary.
This technical study aims to identify key terrestrial and marine spatial constraints within the east coast region establishing an understanding of the study area’s spatial context; to identify and assess the risks that these constraints may present to future offshore wind grid connections under a radial approach; and to consider the extent to which a coordinated model of connection could mitigate these risks.
Two key activities were undertaken:
(i) Strategic constraints mapping to characterise the study area and identify key terrestrial and marine spatial constraints, risks and opportunities; and
(ii) Development and assessment of hypothetical offshore wind development and grid connection scenarios to evaluate radial and coordinated approaches to connection.
This report includes:
- High level characterisation of the East Coast study area.
- Key findings from the analysis of alternative grid connection scenarios.
- Spatial characterisation work and scenario assessments; and
- Conclusions and recommendations.
Spatial constraints vary widely across the region. However, they all potentially influence development of grid connection infrastructure, particularly in terms of the availability of suitable landfalls or proximity of potential grid connection points within coastal areas. Whilst these issues are common to both radial and coordinated models, prolonging the radial model will be less sustainable in the long term given that radial connection, by its nature demands more landing sites for the same capacity of offshore wind when compared to coordinated solutions. Therefore, long-term availability of suitable landfall sites was identified as a risk to future offshore wind deployment, although the significance of this risk varies across the study area.
Several approaches to coordinated grid connection were considered and compared to the radial approach. In all coordinated scenarios, the amount of physical infrastructure required was reduced compared to the radial model. However, depending on the approach adopted, coordination may require additional infrastructure not required in a radial model, including offshore ‘hubs’, coastal ‘nodes’ and additional subsea cable routes connecting offshore wind farms to ‘hubs’ or ‘nodes’.
A coordinated model of infrastructure development will have spatial benefits compared to the radial model. Transitioning to such an approach over the medium to longer term could more effectively support the future deployment of offshore wind as it would facilitate a reduced spatial impact, particularly in inshore and coastal parts of the study area. However, radial models may continue to play a role while technological and regulatory barriers to more coordinated designs are overcome. Furthermore, the location and timing of future offshore wind development will also determine the availability of opportunities for coordinated approaches.
Further work, beyond this study, could help remove barriers to development coordinated offshore grid connections and transmission infrastructure, including improved spatial planning with links to future leasing rounds.
See appendices here.