A blog by Bless Kuri, Head of Transmission System Planning and Investment

In our role as owner of the Transmission network in the north of Scotland, a key license obligation is to ensure a reliable, coordinated and efficient network for our customers, host communities and GB consumers. In addition to investing in our existing infrastructure, this also involves looking ahead to understand what future developments may be required, in our licence area and beyond, based on the balance of future electricity generation and demand requirements, economics and customer need.

Understanding the future requirements of the network also is very important as we prepare for the next price control, RIIO-T2, from 2021 onwards.

Working with National Grid Electricity System Operator (NGESO), and the other GB Transmission Owners (TO), we continually review the potential transmission network requirements arising from different scenarios for future demand and generation looking ten years ahead and beyond. This allows us to identify parts of the network that may need strengthening or additional support and begin work on the long-term investments needed to meet the requirements of our demand and generation customers in the future.

In January this year, NGESO published its annual Network Options Assessment (NOA) report outlining, based on their independent analysis, which major projects will be required to meet the future needs of GB’s electricity transmission system. The NOA report recommends which investments would best manage the capability of the GB transmission networks against NGESO’s Future Energy Scenarios (FES).

The NOA process takes information from each of the three TOs about their transmission reinforcement options to meet system needs as published in the Electricity Ten Year Statement (ETYS). It combines this with future generation and demand scenarios and carries out a GB wide cost benefit study to allow the NGESO to make independent recommendations for the optimal sequence and timing of transmission investments. The NOA reports makes recommendations to “proceed”, “delay”, “hold”, “stop” or “do not start” each investment in 2019/20.[1]

This year’s report recommends, under all FES scenarios, that the following proposed East Coast reinforcements in our network area “proceed” to support an expected increase in renewable generation capacity during the continued transition to a low carbon economy:

  • East coast onshore 275kV upgrade – upgrading one of the double circuit overhead lines running south from Kintore substation to enhance its capacity at the existing operating voltage of 275kV by 2023.
  • East coast onshore 400kV incremental reinforcement – a further upgrade of the double circuit overhead line running south of Kintore along with upgrades to the existing 275kV lines running between Blackhillock substation (near Keith), Peterhead substation and Kintore substation to operate at 400kV in 2026.
  • Eastern Scotland to England offshore link (Peterhead to Drax) – the construction of a proposed subsea High Voltage Direct Current (HVDC) link from Peterhead substation to Drax substation in the north east of England by 2029.

This builds upon last year’s NOA report recommendations which confirmed that work should proceed to incrementally reinforce and increase the capacity of the existing North East and East Coast transmission system in SHE Transmission’s area. The main difference between this year’s and last year’s report recommendations is that the Eastern Scotland to England offshore link should be extended to connect to Drax substation in Yorkshire, instead of Hawthorn Pit. The link improves power flows from the SHE Transmission area where there is high renewable generation, to high demand in the southern part of England.

This proposed extension to the circuit is intended to deliver best value for energy consumers now and in the future, a principle that we strongly support.

We welcome the recommendations outlined within this year’s NOA report and look forward to working closely with stakeholders and decision makers as we progress these nationally important reinforcements. Further information on SHE Transmission’s progress with the East Coast reinforcements can be found on the following project pages:

North East 400kv: https://www.ssen-transmission.co.uk/projects/north-east-400kv/

Peterhead substation: https://www.ssen-transmission.co.uk/projects/peterhead-substation/

The NOA process is iterative and we will shortly start work on the January 2020 report. This means continuing to assess the appropriate transmission network developments to take forward against the emerging and updated generation and demand scenarios.  In the event of material changes in the scenarios or other development factors, progression of modified or alternative reinforcement schemes may become justified.


[1] Further information on the definitions of each recommendation can be found in Chapter 5 of the report here: https://www.nationalgrideso.com/sites/eso/files/documents/Network%20Options%20Assessment%202018_19%20report.pdf


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