Hebrides and Orkney – Future Load Growth Investigation

Regen has been working with Scottish and Southern Electricity Networks (SSEN) to collate evidence on the future electricity load growth on the Outer Hebrides, Inner Hebrides and Orkney. This work will help SSEN to better understand what investment is needed in the islands’ electricity networks, including the subsea cables that connect them to the mainland.


Project duration: October 2023 – February 2024

Project lead: Becky Fowell, Energy Market Analyst 

Within their RIIO-ED2 business plan, Scottish and Southern Electricity Networks (SSEN) identified the need to replace or strategically reinforce 15 subsea cables that currently connect various Scottish islands to the mainland. Funding for these cables is being explored through SSENs Hebrides and Orkney Whole System Uncertainty Mechanism (HOWSUM) programme of work, which is being assessed across 2024 and 2025.

The evidence cases for these island groups builds on Regen’s ongoing work to deliver SSEN’s annual Distribution Future Energy Scenarios (DFES) assessments for their North of Scotland licence area. They also build on a similar load growth assessment that Regen completed for the Isle of Wight, in SSEN’s Southern England licence area.

The evidence cases provide a summary of the existing electricity network and existing network constraints, alongside a summary of the potential future electricity load growth out to 2050, categorised by:

  • Distributed electricity generation (and relevant transmission-connected projects)
  • Electricity flexibility technologies (battery storage and hydrogen)
  • Electrified transport
  • Electrified heat
  • New property developments

The work also provides insight into additional sources of future electricity load from industries that are not currently included within the DFES technology scope, such as:

  • Maritime (ferries and fishing vessels) and aviation decarbonisation
  • Significant commercial industries (i.e. whisky distilleries, agriculture, aquaculture)

This study is intended to support SSEN to identify future electricity needs across these Scottish Island groups. This will inform the network investment requirements to enable future uptake of renewable generation and low carbon technologies across the islands, allowing for both net zero and security of supply within the island groups.

SSEN have recently published documentations related to their HOWSUM (Hebrides and Orkney Whole System Uncertainty Mechanism) application on their website.

The evidence cases that Regen has provided for each island group can be found below.

Website OH Wording              Website Ork Wording                  Website IH Wording


People on this project

Ray Arrell
Associate Director
Ray is part of the Regen leadership team, overseeing our work and strategic goals…
Becky Fowell
Energy Market Analyst
As an energy market analyst, Becky works with data, visualisation tools and continuous stakeholder…
Shona R
Energy Analyst
Shona is an energy analyst who joined Regen in September 2022 after completing her…
Charlotte Wason
Graduate Energy Analyst
Charlotte is a Graduate Energy Analyst, having previously spent time as a summer intern…

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