The existing electricity network is a distribution network operating at 33kV or below, and the Islands are connected to mainland Scotland by two 33kV subsea cables installed in 1982 and 1998 respectively between Rackwick Bay on Hoy, and Murkle Bay near Thurso. These cables have a total capacity of 40MW and the currently connected generation in Orkney uses all of the available export capacity in the existing 33kV cables.
Demand on the islands ranges from 7MW and 46MW and is secured in the event of a network fault with the assistance of a standby diesel generator installed at Kirkwall.
A number of renewable energy developers in the Orkney Islands have requested a connection to the electricity network. The Orkney connection project would provide a new transmission connection between Caithness and the Orkney Islands, and associated onshore infrastructure required to support this connection.
In response to the feedback received regarding Finstown substation, the overall height of the substation platform has been reduced by a metre compared to the design presented at the latest round of consultation and the height of the bunding that will help screen the substation buildings will also be increased. Whilst there is a limit to the extent in which the substation height can be reduced due to the risk of flooding if the platform height is reduced below ground level, the impact of these latest changes will help further reduce its visual impact, which has been sensitively designed to be in keeping with the Orkney landscape by housing the substation in a number of buildings of similar design and colour to existing agricultural buildings on Orkney. Please note that a larger downloadable version of the comparative visualisations is available from the project documentation tab.
The following visualisations illustrate the recent changes to the proposed Finstown substation following public consultation in late 2018.
Horizontal Directional Drill - Cable landing
Cable trenching - Onshore
Cable trenching - Subsea
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.
Related Projects: Orkney
Related Projects: Orkney
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