Holistic Network Designs | Grid

Offshore wind has been identified as a critical technology in achieving net zero greenhouse gas emissions by 2050.

To help realise this target, a step-change in both the speed and scale of deployment of offshore wind is required.

One of the challenges to delivering the ambition for offshore wind deployment in the timescales required will be making sure that the offshore and onshore transmission network enables this growth in a way that is efficient for consumers and takes account of the impacts on coastal communities and the environment.

The ESO offshore coordination project, which contributes to the BEIS-led OTNR1 , was set up in March 2020. Phase 1 of the project assessed the costs and benefits of a coordinated offshore network compared to the current radial connection approach. This assessment considered the technical considerations to achieve that, and how the offshore connections regime could change to drive greater coordination.

In December 2020 we published our Phase 1 final report2, with analysis indicating that: • Adopting an integrated approach for all offshore projects to be delivered from 2025 has the potential to save consumers approximately £6 billion in capital and operating expenditure between now and 2050. •

There are also significant environmental and social benefits with an integrated approach, as the number of new electricity infrastructure assets, including cables and onshore landing points, could be reduced by around 50 per cent. •

However, this approach was conceptual and did not take deliverability into account. Delivering the extent of integration required in this timescale would be extremely challenging and potentially endanger the target of 40 GW of offshore wind capacity by 2030. • An integrated approach for projects to be delivered from 2030, compared to the status quo, would deliver savings to consumers of around £3 billion and could facilitate a 30 per cent reduction in the new electricity assets associated with these offshore connections.

As part of Phase 2 of the project, BEIS and Ofgem requested that we deliver a Holistic Network Design (HND) for a coordinated onshore and offshore network. The HND will need to support the connection of 40 GW of offshore wind by 2030 in Great Britain, with 11 GW of that in Scotland as well net zero by 2050 for GB and by 2045 for Scotland.