Ultimate responsibility for the requirement for extra electricity transmission infrastructure lies with the UK Government. In April 2022, the Conservative UK Government published the British Energy Security Strategy (BESS) which included a new target to deliver 50GW offshore wind capacity by 2030. The aim of this was to provide the increased electricity capacity required due to the decarbonisation of heating and transport, population growth, economic growth, and to reduce instances of curtailed renewable generation due to insufficient capacity.
 
Two months after the publication of the BESS, the National Grid Electricity System Operator (ESO) published the Pathway to 2030 Holistic Network Design (HND). It provided connection recommendations for 23GW of offshore wind and the associated transmission network infrastructure. This included a recommendation for an existing line upgrade running through Angus, referred to as the East coast onshore 400 kV Phase 2 reinforcement (Scotland). This upgrade had already been identified as necessary in previous iterations of the Network Options Assessment by the Network Energy System Operator (formerly Electricity System Operator) and was confirmed as necessary in the HND. This line was also one of the 11 NOA Options classified as HND Essential requiring acceleration to 2030. 
 
Please see below maps which detail the HND new offshore line proposals. Please note these do not include all recommended routes, only those newly recommended in the HND.
 
Following the HND is the (current) Detailed Network Design (DND) phase where more accurate and specific proposals will be made by the parties responsible for delivering each asset i.e. the network operator (for the East coast onshore 400 kV Phase 2 reinforcement this is SSEN).
 
The need for the network reinforcements has also been approved by the GB energy regulator, Ofgem, as part of its Accelerated Strategic Transmission Investment (ASTI) framework decision in December 2022. The ASTI is a set of investments and regulations applied to certain projects to speed up their development. This includes exempting projects from competition, and streamlining of the process for assessing and funding projects that are selected for ASTI. The East Coast onshore 400kv Phase 2 reinforcement was selected as an ASTI project. This decision was partially due to the fact the HND noted the project would likely be finished by 2032, when the extra transmission capacity is required by 2030 to meet UK Government targets.