inveraray to crossaig overhead line reinforcement · inveraray to crossaig overhead line...

Inveraray to Crossaig Overhead Line Reinforcement

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About Scottish Hydro Electric (SHE) Transmission plc Scottish and Southern Energy Power Distribution is part of the SSE plc group of companies. We own, maintain and invest in the electricity networks in the north of Scotland – the electricity transmission network (132 kV and above) and the electricity distribution network (below 132 kV). In Scotland, Scottish and Southern Energy Power Distribution is made up of two businesses: Scottish Hydro Electric Transmission (SHE Transmission) owns and

maintains the electricity transmission network across the north and west of Scotland, in some of the UK’s most challenging terrain; and

Scottish Hydro Electric Power Distribution (SHEPD) operates the high and low voltage electricity network that distributes electricity to around 700,000 customers in north mainland Scotland and the Scottish islands.

SHE Transmission owns around 5,000 km of electricity transmission infrastructure which spans about 70% of the land mass of Scotland. Electricity networks like this provide a physical link between electricity generators and electricity users. We have three main objectives over the next decade: To keep the lights on for our customers; To invest for a greener future; and To minimise, as far as possible, our impact on the environment. Our network crosses some of the UK's most challenging terrain - including some circuits which are over 750 metres above sea level and up to 250 km long. The landscape and environment that contribute to the challenges we face also give the area a rich resource for renewable energy generation. There is enough demand to connect from new wind, hydro and marine generators which rely on us to provide a physical link between the new sources of power and electricity users. We are delivering a major programme of investment to ensure that the network is ready to meet these needs.

Keeping the lights on and supporting growth

Safety first Safety is our first priority in everything we do. We aim to be among the safest companies in the world and will keep looking for new ways to keep our staff, contractors and the public safe. Last year our staff made 96 visits to schools in their own communities to teach children how to be safe around electricity. When it comes to safety, we think you can’t start early enough.

Proud to be an active part of the community Our volunteering programme means every member of our staff can take a day of their time each year to work on a community project of their choice. In the five years since the launch of the programme, we’ve helped over 2,100 projects, with big-hearted employees dedicating an amazing 24,000 days (equivalent to 194,000 hours) to projects that matter in the communities where we live and work. If there is a community or charity project that you think our staff might be able to help with, just ask a member of the team for more information.

Investing in skills for the future We are committed to investing in the long term future of our business and of the communities where we work. That’s why we offer a range of industry-leading training and apprenticeship programmes, with opportunities for everyone from school-leavers to graduate engineers. In recent years, we have also delivered an award-winning transmission trainee programme in partnership with Inverness College UHI and Balfour Beatty. To find out more about our training and career opportunities, check regularly at www.sse.com/careers


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Project Background As a result of a number of renewable energy projects on the Kintyre Peninsula and throughout Argyll requiring a connection to the transmission network, and to ensure security of supply to the region, we need to reinforce the existing transmission network serving the region. The area between Inveraray and Crossaig is currently served by a double circuit 132 kV overhead line, stretching approximately 84 km in length between Inveraray switching station and Crossaig Substation (currently under construction). The line extends south to Carradale substation and this section of the line between Crossaig and Carradale is currently being rebuilt as part of the Kintyre-Hunterston project (completion 2015). We need to identify a suitable route for a new overhead line to be constructed between Inveraray switching station and Crossaig substation. To maintain supply, the existing line would remain in place and operational whilst the new, replacement line is being constructed. We are here today seeking views from local residents about our proposals.

Generation Connections in the Area Under the terms of our license as an owner and operator of the electricity transmission network, we are obliged to develop and maintain an efficient, coordinated and economical system of electricity transmission. Our responsibilities also extend to ensuring that there is sufficient network capacity and a connection for developers who wish to export their generated electricity to the national grid. If a generator applies to connect to our network, we are required to facilitate this under the terms of our licence. By reinforcing the existing transmission network between Inveraray and Crossaig, new generation will be able to connect to the main transmission system and centres of demand. At this time in the Argyll and Bute area, we have connected 280 MW of generation, and have committed to connecting a further 250 MW. The adjacent table confirms our existing and contracted wind farm generation agreements in this area.

Connected Generation

Consented Generation

Contracted Generation

Carraig Gheal A’Chruach Musdale

An Suidhe Freasdail Ardchonnel

Beinn an Tuirc I Cour Beinn an Tuirc II and III

Allt Dearg Allt Rhuba

Tangy III

Picture of Allt Dearg Wind Farm


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Project Description The aim of the project is to reinforce the existing transmission network in the region to enable renewable energy projects to connect to the electricity network, and to ensure security of supply. The main elements of the project are shown on the Project Overview map below and are as follows: Connection to an existing switching station in Inveraray; Construction of a new overhead line capable of operating at

132 kV or 275 kV between Inveraray and Crossaig (connecting to Port Ann substation);

Decommissioning / removal of the existing 132 kV

transmission line between Inveraray and Crossaig; and Connection to the 132 kV substation at Crossaig (which is

currently under construction and due for completion in 2015). We are currently undertaking a route options appraisal to identify a technically efficient and economic route, taking into account environmental factors to minimise any potential adverse impacts on the environment and local communities.

Project Timeline

The project is currently at a very early stage in the development process and timescales are indicative at this stage. Complete feasibility design 2015 Progress Environmental Impact Assessment (EIA) for the new overhead line 2015 Submit Section 37 Consent Application for the new overhead line 2016 Contract tendering and procurement 2015 / 2016 Land wayleaves agreements progressed 2015 / 2016 Consent decision anticipated 2017 Construction start 2017 / 2018 Phased completion and commissioning 2020 / 2021


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Overhead Line Route Selection

We have undertaken a detailed assessment to identify potential overhead line route corridors. The approach in identifying and assessing possible corridors capable of accommodating the proposed new overhead line is consistent with our guidance on the routeing of high voltage steel lattice towers. The guidance advocates the application of a hierarchical approach to routeing which first avoids major areas of highest amenity, then avoids smaller areas of high amenity, and which then considers factors such as backdrop, woodland and orientation. Using this guidance Route A corridor was identified as the preferred option. Alternative route corridors have been identified and these will remain under considera-tion during the initial stages of this project (see Route Corridors B and C on the adjacent figure). The proposed corridor has emerged as the preferred route option due to it having a lower potential impact with key environmental features and sensitivities compared to the existing overhead line route: It seeks to minimise potential impacts with national,

regional and local landscape designations, as well as residential amenity, taking into account settlements in the vicinity of the corridors; and

It seeks to minimise potential impacts on international and national nature conservation designations.

We will continue to work with environmental consultants and overhead line engineers to identify a technically feasible and economically viable transmission overhead line route within the preferred corridor which will give rise to: The least disruption to the amenity of people living

and working in the area; The least impact on the physical and natural

environment and on nationally important species, habitats and cultural assets;

The least disruption to current land use and management practices; and

The least disruption to existing and proposed infrastructure.

The proposed overhead line would require consent under Section 37 of the Electricity Act 1989 and would be subject to determination by the Scottish Ministers. This would be subject to rigorous environmental appraisal which would assess impacts on ecology and ornithology; soils and hydrology; cultural heritage; habitat and flora; and landscape character and visual amenity. The appraisal would evaluate potential environmental impacts of the preferred overhead line route and identify where appropriate measures to mitigate against such impacts.

Consenting Process


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Overhead Line Tower Design

The towers proposed for the new overhead line will be larger than the towers on the existing line between Inveraray and Crossaig. This is to allow future upgrading to operate at 275 kV to accommodate demand for generation connections in the area. One advantage of the use of larger towers is that the distance between towers is greater resulting in less towers in total being required. The existing line comprises 384 towers between Inveraray and Crossaig, approximately 26 m in height (excluding extensions) with spans between towers of around 220 m. The towers on the proposed line would be approximately 40 m in height (excluding extensions). This increase in height would allow increased spans (300 m to 350 m) and a reduced number of towers along the route (anticipated to be approximately 250). The drawings below give an indication of how the proposed towers will look in comparison to the existing towers.

High voltage overhead line construction typically follows a standard sequence of events which are: Complete pre-construction surveys, as required by a construction environmental management plan; Establish access (including any necessary vegetation management); Install tower foundations; Assemble and erect towers; Erect temporary scaffolds and protection to roads, railways and rivers; Erect conductors (wires); Dismantle and remove temporary scaffolds and protection; and Re-instate tower sites and remove temporary access tracks. Foundations A tower compound would be established at each tower location, within which foundation installation and subsequent tower erection would take place. Each compound would be fenced for safety. Foundation types and design for each tower would be confirmed following detailed geotechnical investigation at each tower position. Tower Erection Tower steelwork is generally delivered to site either as individual steel members or as prefabricated panels, dependent on the method of erection for the tower. The preferred method of assembly and erection would use a crane. Conductor Stringing Prior to stringing the conductors, temporary protection measures (normally netted scaffolds), would be erected if necessary, for features such as roads, railways and existing transmission infrastructure to be crossed. Conductor stringing would be carried out by running a pilot line through rollers on the towers, and a winch would be used to pull the conductor off drums onto the towers.

Construction of Towers and Overhead Lines

Existing Tower

Proposed Tower


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How do I have my say?

We are keen to receive feedback from the local community and other interested parties on our proposal. Comments can be submitted as follows:

At the exhibition today – complete a Comments Form and place it in the box provided.

By post – complete a Comments Form and post it to our Liaison Manager (details below).

By email – complete a Comments Form and email it to our Liaison Manager (details below).

Comments forms and all the information from today’s event will also be available to download from the project website at www.ssepd.co.uk/inveraraycrossaig Information can also be posted out to you by our Liaison Manager upon request. Please make your comments as specific as possible in order to help us consider them in relation to our proposal. The closing date for comments for this exhibition is Friday 28th November 2014. Contact details for the Project Liaison Manager are as follows: Samantha O’Connor Corporate Affairs Inveralmond House, 200 Dunkeld Road, Perth, PH1 3AQ Email: [email protected] Mobile: 07584 313059

Photographs of the existing overhead line

inveraray to crossaig overhead line reinforcement · inveraray to crossaig overhead line...

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