The project comprises of the following elements:
Knocknagael to Tomatin - Construct approximately 20km of 275kV double circuit overhead line between Knocknagael substation and the proposed Tomatin substation on a new alignment.
Knocknagael to Farr - Dismantle the existing 132kV overhead line between Knocknagael substation and Farr substation
Tomatin Substation – Construct a new 275/132kV substation near Tomatin, adjacent to the existing Beauly to Boat of Garten 132kV double circuit overhead line.
Knocknagael Substation – existing 132kV overhead line from Beauly into Knocknagael via a new sealing end compound (where overhead lines terminate onto underground cables), and connect the proposed Knocknagael to Tomatin 275kV overhead line via a new sealing end compound.
As the transmission licence holder in the north of Scotland we have a duty under Section 9 of the Electricity Act 1989 to facilitate competition in the generation and supply of electricity. We have obligations to offer non-discriminatory terms for connection to the transmission system, both for new generation and for new sources of electricity demand.
The aim of the project is to enable renewable energy to connect to our transmission network. Under our Network Operators Licence this connection should be efficient, co-ordinated and economic, whilst having the least possible impact on the environment.
With the exterior complete and the work on the interiors progressing well, October 2018 saw the delivery of the two transformers which will sit at the heart of Tomatin Substation.
When it comes to the actual transformers themselves, the facts and figures make for interesting reading:
The transformers were manufactured in Milan, shipped to Inverness via Venice and then delivered by road to Tomatin, a total of over 4,000 miles.
Each transformer weighs 194 tonnes, which is roughly equivalent to 43 African elephants
The specialist haulage vehicles, including 3Nr. Large traction lorries, known as Trojans, each weigh 460 tonnes (loaded) and have a total of 280 wheels
Alistair Muir, SSEN Transmission’s Project Manager, said: “Watching the transformers make the final part of their journey down the A9 and on to our site at Tomatin was incredibly satisfying, as it marked the culmination of many months of hard work and planning behind the scenes by not only our own team, but also the manufacturers in Milan and our specialist haulier.”
Now that the transformers are in place, the construction phase of Tomatin substation is nearing completion, and SSEN Transmission is hoping to have it connected to the grid and energised in July 2019.
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.
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.
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.
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.
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.
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.
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