The North Argyll project aims to reinforce the existing transmission network in the region to enable renewable energy projects to connect to the network and to ensure security of supply.
The main elements of the project are
- Construction of a new 275/132kV Creag Dhubh substation (formerly referred to as North Argyll substation) in close proximity to the existing Inveraray to Taynuilt 132kV overhead line
- Construction of a new 275kV overhead line between the proposed Creag Dhubh substation and the existing Dalmally substation
- Rebuild of the existing 132kV overhead line between Taynuilt and the proposed Creag Dhubh substation
- Decommissioning the existing 132Kv overhead line between Taynuilt and the proposed Creag Dhubh substation
A requirement for the projects has been established following analysis of the existing network. We have a statutory obligation to make sure the electricity transmission network is capable of safely connecting and transmitting the energy produced by generators.
The data in this map is provided for indicative purposes only and may be subject to change. Scottish Hydro Electric Transmission plc do not accept responsibility for its accuracy, completeness or validity. The data should not be copied, reproduced or utilised externally without permission.
Scottish and Southern Electricity Networks is the trading name of Scottish and Southern Energy Power Distribution Limited, Scottish Hydro Electric Transmission plc, Scottish Hydro Electric Power Distribution plc and Southern Electric Power Distribution plc.
It’s the highest voltage electricity network in the UK – the ‘motorway network’ of the energy world. It transmits large quantities of electricity over long distances via wires carried on a system of mainly metal towers (pylons) and large substations. Transmission voltages in Scotland are 132kV, 275kV and 400kV. Larger generation schemes usually connect to the Transmission system.
The lower voltage parts of the system are called distribution networks. In Scotland, these local networks operate below 132kV whereas in England the distribution network includes 132kV.
Investments in projects are made by SHE Transmission plc. Electricity transmission companies are authorised to recover the costs of such investments through 'use of system' charges which are levied by National Grid Electricity Transmission plc on generators and suppliers of electricity. Suppliers recover their costs from all electricity customers. In order to protect the interests of customers, the transmission companies have to demonstrate to the energy regulator, Ofgem (Office for Gas and Electricity Markets) that proposed investments are necessary, are efficient and are economical so that the charges which are ultimately levied on all electricity customers are justified.
This means SHE Transmission is subject to a funding mechanism established by Parliament and regulated by Ofgem. Cross subsidies between different businesses in the SSE group is not permitted.
SHE Transmission are regulated by the Office for Gas and Electricity Markets (Ofgem), the regulator responsible for representing consumers' interests. Electricity consumer interests are therefore one of our key drivers and this is enshrined in our statutory duties under the Electricity Act.
In particular we have a statutory duty to develop, maintain and operate an efficient, economic and co-ordinated transmission system. Since the costs of these projects will ultimately be paid for by electricity consumers, we have a responsibility to take cost into account with due weighting in a comparison against other important factors.
In response to connection applications from developers of renewable generation across the Argyll region, SHE Transmission identified the need for additional transmission capacity to accommodate the connection of these developments and to allow for the export of the generated power to areas of demand. An options assessment was undertaken by SHE Transmission to consider different reinforcement solutions. This assessment identified the proposed North Argyll reinforcement (in conjunction with the Inveraray - Crossaig project) to be the solution that best meets our licence obligation to develop and maintain an efficient, economic and coordinated transmission system .
A number of options were considered that included a mix of overhead line and cable technology, both underground and submarine cables laid in Loch Awe.
A submarine cable option within Loch Awe was discounted due to a number of significant routing and installation constraints. The following land cable options were also considered;
Option A - a route that followed the main A85 trunk road,
Option B - a route that crossed the flood plain in front of Stronmilchan, and
Option C - a route that traversed the hillside behind Dalmally beyond the existing Scottish Power Energy Networks overhead line.
Each option poses significant engineering challenges including:
In response to feedback from statutory stakeholders during previous public consultation, SHE Transmission appointed an experienced Cable Engineering Consultant in December 2016 to further explore the feasibility of undertaking a submarine cabling solution at Loch Awe.
The survey found that any potential route would be constrained by the existing configuration of the underwater terrain in and around Loch Awe being very steep sided with a narrow area of valley floor in the northern and southern parts of the route, combined with large areas of shallow water in the centre. To produce the necessary circuit capacity requirements, 6 x 3-core cables would be needed requiring approximately 66 x 50 tonne cable drums. The Consultant was able to design only two potential routes to achieve this requirement and which could only be achieved by:
a) Inserting cables between the identified routes . This was considered inadvisable by the Consultant, as it would not leave room for safe grappling of cables during repair work, or for laying of bights after repairs. In essence, a repair might well involve installing a completely new cable. Additionally, in the narrowest pinch point, the separation of the cables would approach the point at which mutual heating might become an issue.
b) Routeing some of the cables through shallow water. This second option was also considered inadvisable as areas of shallow water would make the cables susceptible to abrasion by water movement during bad weather, potentially compromising their electrical integrity. Normal practice would be to protect the cables with a layer of rock however due to the landlocked nature of the loch, and the lack of existing suitable vessels already on the loch, rock dumping operations cannot be carried out
Other installation constraints such as the following were also given by the Consultant:
Given the range of logistical constraints identified by the Consultant and the inadvisability of the route options, we are pursuing alternative land based engineering solutions.
If a developer decided not to proceed with their project (for whatever reason) SHE Transmission would review whether any identified transmission works were still required (either in part or as a whole). If it was determined that the works were still required then SHE Transmission would proceed with the planned reinforcement. If it was determined that the solution currently being promoted was not required then SHE Transmission would seek to identify an alternative solution that satisfied the requirements of the remaining developers.
The proposed overhead line will be approximately 13km in length. Subject to topography and ground conditions, the current design is for the construction of a double circuit 275kV overhead electricity transmission line supported by 48 towers with spans between each tower of 184 to 343 metres. The final number of towers will not be known until final detailed engineering studies are complete.
Subject to topography, angle of the line and altitude the height may typically vary between 40-59 metres to ensure specified electrical clearances are maintained. The final height of each tower will not be known until final detailed engineering studies are complete.
A key objective when designing a route for an overhead line is to try and avoid proximity to as many residential properties as possible. SHE Transmission endeavours to align the route to stay at least 100 metres from any residential property. Use is made of visualisation techniques to assist in the route selection and 3-dimensional modelling techniques have been employed to assess the impact on individual properties. The analysis of the preferred route shows the closest property to be 110 metres from the overhead line.
The model was provided to allow members of the local community to view a 3-dimensional visualisation of the proposed overhead line from key local areas and individual postcodes. These visualisations set the proposals to scale within the local environment and incorporated a data set called National Tree Mapping (NTM) for tree plotting in order to present as accurate a representation as possible. This model was prepared on our behalf by a specialist company called 3D WEBtech.
Compensation will be paid to landowners on whose land the line is to be erected on and that will be agreed on a case by case basis in line with statutory provisions.
The infrastructure being considered under the VISTA project concerns existing assets located within, or near, National Parks and National Scenic Areas. The purpose of the project is to reduce the visual impact of existing infrastructure within these designated landscapes. The funding mechanism for VISTA cannot be used to mitigate the visual impact of new or planned infrastructure projects.
The designation of an Area of Panoramic Quality (APQ) does not mean that development cannot take place. Development is still permitted in an APQ subject to the grant of Section 37 consent by The Scottish Ministers.
EMFs are considered as part of the Environmental Impact Assessment (EIA) process. SHE Transmission are obliged as part of our transmission licence obligations, to ensure that our assets operate within the limits as specified in guidance from the UK Government. These limits are based on the advice of the Government’s independent scientific advisers - Health Protection Scotland and Public Health England (formerly Health Protection Agency, Formally NRPD) - who ensure the appropriate level of protection for the public from these fields.
Health Protection Scotland and Public Health England are appointed by the Secretary of State to protect the public from dangers to health. These organisations conduct and review relevant research and ensure that the guidelines for limiting exposure are based on the most appropriate available scientific information.
Further information on the guidance can be accessed on the UK Government website.
Information on the research into a possible link between EMFs generated from electricity transmission infrastructure and human health is documented in the Energy Networks Association (2017) publication “Electric and Magnetic Fields: The Facts”.
The preferred alignment has been chosen to avoid those habitats most sensitive to the development. However, it is possible that the development will have some effect on wildlife during construction. SHE Transmission will carry out protected species surveys during the Environmental Impact Assessment (EIA) process to identify the locations of any protected species and employ appropriate species mitigation plans.
SHE Transmissions survey work has not detected any osprey nests or osprey flights in the vicinity of the preferred alignment. The survey identified a total of 32 flights during the flight activity surveys (comprising the following species; greylag goose, cormorant, mallard, oystercatcher, curlew, snipe, hen harrier, merlin, peregrine falcon, golden eagle and white-tailed eagle). Also, 33 breeding bird territories were recorded in the Breeding Bird survey area (comprising the following species; common buzzard, common sandpiper, curlew, oystercatcher, snipe, mallard, goosander, great black-backed gull and sand martin).
We are always careful to minimise any impact on tourist attractions and early consultation will assist in identifying any concerns.
We will also look carefully at what impact construction might have during key events in local areas with the aim of minimising any inconvenience. Any potential impact on tourism interests will be assessed through the Environmental Impact Assessment and will be documented in the Environmental Statements.
An initial review of the landscape effects of alternative route and alignment options was considered and published in the Route Consultation Document (July 2017) and Alignment Consultation Document (March 2018) available from the ‘Project documentation’ tab on the project webpage. Once a proposed alignment is identified at the end of the alignment consultation process, a detailed landscape and visual assessment will be completed and included within an Environmental Impact Assessment (EIA) Report. This will consider the significance of effects on landscape and visual receptors, including key views like the A85 trunk road, tourist locations and private residences.
The Holford Rules originated in 1959 as the result of work by Lord Holford, a part-time member of the Central Electricity Generating Board (National Grid's predecessor). The Holford Rules have been augmented by both National Grid and SHE Transmission plc to reflect environmental legislation and best practice in recent years. We have continued to use them as a valuable set of guidelines for reducing the impact of our assets on landscapes.
The guidance recommends appropriate application of the Holford Rules to inform routeing. These rules advocate the application of a hierarchical approach to routeing which first avoids major areas of highest amenity, then smaller areas of high amenity, and finally considers factors such as backdrop, woodland and orientation. The Holford Rules apply the term ‘amenity’ to refer to environmental designations and classifications such as Natura 2000 sites, Sites of Special Scientific Interest (SSSI), Scheduled Monuments, Listed Buildings, National Parks.
The guidance also recognises that the key effect of overhead lines is visual and it advises that the routeing of overhead lines should consider the types of mitigation (screening) that could offset any visual effects.
In their National Policy Statement EN-5, the Government has stated that the Holford Rules “should be followed by developers when designing their proposals.” Their use is therefore Government policy, rather than a voluntary choice of SHE Transmission plc.
Based on feedback received during the March 2018 consultation events, SHE Transmission have committed to carrying out further study work into the potential for undergrounding in places of local sensitivity. This study work will further explore the currently identified routes and seek to find potential alternative underground options. We anticipate to receive the outcome of further cable studies in Q1 of 2019 and will engage with the community thereafter to discuss conclusions.
The cost of an underground cable solution is unique to the design as each will consider factors such as terrain, ground conditions, access requirements, route lengths, number of crossings of water courses, bridges, roads, railways, electrical cable design, network system requirements and the like. Typically, in comparison to an overhead line, this can vary from between 3 and 5 times more expensive, and in some cases can be considerably more.
The main purpose of the new Creag Dhubh substation is to connect two overhead lines; the existing 132kV overhead line between Inveraray and Taynuilt, and the proposed new 275kV overhead line between Creag Dhubh and Dalmally. The substation will also contain the necessary transformation equipment (and associated switchgear and busbar) to step the voltage up from 132kV to 275kV.
The size of the site is dictated by the electrical voltages, the types of equipment that needs to be accommodated on the site and the space required to maintain safe working conditions (e.g. electrical clearances) for our operational staff.
There are two main types of electrical switchgear that can be utilised, which differ in how they insulate against the high voltages they carry. This means they vary in terms of their size and cost:
The preferred design for the substation utilises a combination of the two switchgear types; GIS for the main banks of electrical components such as circuit breakers, with AIS for the connections to the overhead lines and transformers themselves which has allowed SHE Transmission to optimise the substation design in terms of size, operability and cost.
There is potential for travel disruption during construction, when we take delivery of key plant items or because of increased volumes of traffic on the local road network. Disruption will be minimised and typically controlled through an agreed Traffic Management Plan with Argyll and Bute Council as part of any consent conditions which will be contained in the consent under Section 37 of the Electricity Act to be granted by The Scottish Ministers for the project. SHE Transmission aims to ensure that construction traffic uses the roads safely and that any inconvenience to the public is kept to a minimum whilst maintaining a safe environment for the workforce and other road users.
As part of the Environmental Assessments, potential impact from construction noise will be evaluated and mitigation measures instigated where necessary. These are controlled through Consented conditions.
Discussions will be held with landowners and surveys completed during development of the Projects to locate private water supplies. The outcome of these surveys and subsequent assessment will be documented in the Environmental Statements and supplied to the contractor to protect water supplies.
The Scottish Ministers are responsible for determination of applications submitted under Section 37 of the Electricity Act 1989. Both statutory consultees and members of the public have the right to submit their representations on the application. All representations will be considered by Scottish Ministers in their determination of the application.
The Office for Gas and Electricity Markets (Ofgem), as the regulator, has to approve all investment so project proposals are developed under license conditions.
Preferred route corridors chosen will comply with revised ‘Holford Rules’ which are the recognised industry approach to routeing overhead lines amended to reflect Scottish circumstances.
SHE Transmission expect to submit their application for Section 37 consent under the Electricity Act to The Scottish Minsiters in Quarter 2 of 2020. The application will be advertised and opportunities for representations will be available at that time. Planning applications for the substations will be submitted to the relevant Local Planning Authority and opportunities for submission of representations will be available at that time.
SHE Transmission will continue consulting with the Scottish Government Local Energy and Consents Unit, Argyll & Bute Council and other key statutory bodies as well as the local community prior to submitting a formal application.
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