SSEN presents final design for Finstown substation
SSEN Transmission is conducting a final round of consultation to present its proposed design for Finstown substation in advance of submitting a planning application for the development.
A consultation event will take place at the Ayre Hotel in Kirkwall on Wednesday 6 February from 2pm to 7pm to provide the local community the opportunity to view the proposed design. This will include a 3D model allowing anyone interested to view the proposed substation from any location on Orkney where it will be visible. SSEN has also published a number of animations and visualisations to show how the substation will look against the Orkney landscape.
The substation is a critical component of SSEN’s proposed transmission reinforcement from Orkney to the mainland, which is required to support the growth of renewable electricity generators across Orkney looking to connect to the main GB transmission system. The progress of the reinforcement remains subject to all planning and regulatory approvals.
Throughout the development of the project, SSEN has consulted widely with the local community and key statutory stakeholders and has made a number of changes to the substation’s design in direct response to feedback received. This includes:
- A decision not to use steel lattice towers to connect the substation to the subsea cable at Warebeth, which will instead be connected by an underground cable.
- Rather than site the substation in one large building it will instead be housed in a number of smaller buildings, in keeping with existing agricultural structures already existing in Orkney.
- These buildings will be of varying heights and shapes with colours in a selection of different natural tones to reflect a group of agricultural buildings.
- The connecting overhead line (OHL) to the north of the substation will be undergrounded for a distance of approximately 1km. This will avoid the OHL being sky-lined when viewed from the World Heritage Site monuments and reduce cumulative effects at the substation.
- From the south, the overhead line is being undergrounded for approximately 70m. Additional undergrounding here would be more detrimental to the habitat in the Heddle Local Nature Conservation Site, and views from the south are not considered as sensitive.
- To help minimise its visual impact, SSEN has lowered the platform height from that proposed in September 2018, using the additional excavated materials to increase the landscaping (landform) around the substation, reducing visibility of the site further.
Based on the current design of the substation, SSEN no longer believes there is a significant flood risk at the site due to mitigation measures introduced, such as the diversion of a nearby water course. However, in addition to the cost and local disruption associated with the significant earth works and material removal that would be required to further lower the platform height, the ground water encountered during the exploratory borehole investigations would pose complications to foundations construction as well as presenting technical and safety challenges associated with the earthing of the platform.
Any further reduction of the platform height would come at a significant cost, which would risk the economic viability of the project due to the impact on the costs that generators would have to pay to connect and the regulatory business case. Furthermore, as energy bill payers from across GB will ultimately pay for the reinforcement, SSEN has a duty to ensure its proposal is economical and represents value to the GB consumer.
Commenting ahead of the consultation event, Keith Inglis, Lead Project Manager, said:
“Throughout the development of the project we have worked hard to factor into the substation’s design the feedback received from both statutory and non-statutory consultees and the local community.
“Whilst it has not been possible to respond positively to all feedback, such as those calling for the platform height to be further reduced, we firmly believe we have worked hard to balance the visual impact of the substation against the various engineering, environmental and economic considerations that we have to factor in to our design.
“We look forward to presenting our final design to the Orkney community and hope they will agree that its overall visual impact is acceptable, particularly when viewed from the World Heritage Site Monuments.”
Subject to planning and regulatory approvals, SSEN now intends to start construction in April 2020 with an energisation date of spring 2023. This will be subject to regulatory approval of the scheme by Ofgem as well as the various statutory consents.
As well as the substation element of the proposed reinforcement, SSEN is also developing the onshore infrastructure required to connect the various proposed renewable developers across Orkney to Finstown substation. This part of the overall reinforcement project is still in development with the next round of consultation currently planned for summer 2019, at which point there should be greater certainty over the generation background. Currently around 25% of this infrastructure will be undergrounded, which when coupled with SSEN’s commitment to underground the main cable from Finstown to Warebeth, brings the total infrastructure to be undergrounded to 33%.
For more information on the Orkney transmission reinforcement project, including animations and visualisation of the proposed substation, please visit: https://www.ssen-transmission.co.uk/projects/orkney/