Project Background The Route Selection Process Tower Construction This proposal is part of the reinforcement of the electricity We have worked closely with a team of environmental The OHL will be constructed using self-supporting lattice transmission network, envisaged by the National Planning consultants and overhead line engineers to identify a steel towers. The towers used for the 275 kV OHL will vary Framework (NPF2) and the Energy Networks Strategy technically feasible (both in terms of constructability and long in height between 32m and 52m to accommodate changes Group. Analysis of the existing transmission network in the term maintenance), economically viable, new transmission in topography and where the line crosses roads and rivers, north of Scotland identified the need for increased network OHL which gives rise to: although the height will generally be in the region of 40m. capacity to facilitate the transmission of renewable The 132kV OHL towers will vary in height between 23m and generation projects north of Beauly including onshore / • The least disruption to the amenity of people living and 38m, although the height will generally be in the region of offshore wind and marine and tidal generation. This increase working in the area; 28m. in network capacity can only be achieved by undertaking • The least impact on the physical and natural environment, reinforcement of the transmission network in the north of and on nationally important species, habitats and cultural The spacing between towers will vary depending on Scotland. assets; topography, altitude and land usage. The height and • The least disruption to current land use and management distance between towers will be determined later in the Project Description practices; and design process; however the spacing will be generally in the • The least disruption to existing and proposed infrastructure range of 260-360 m for the 275 kV towers and 200-300 m and other economically beneficial uses of land. for the 132 kV towers. The aim of the project is to strengthen the high voltage network in Caithness with the replacement / upgrade of the A number of 2km wide route corridor options were assessed, Thurso Substation Description existing 132 kV overhead line (OHL) between the taking into account the technical requirements to connect to the substations at Dounreay, Thurso and Mybster with new existing electricity network. A process of analysis and higher capacity infrastructure. The main elements of the comparison of potential routes within the 2km corridors was • A new access will be constructed from the A9 to the project are as follows: then followed. north-east of the proposed site. • The footprint of the proposed substation and associated • Construction of a new double circuit 275 kV OHL from the The assessment has been based on: infrastructure would be approximately 9.1 Hectares Dounreay substation to the proposed 275kV / 132 kV including embankments. The construction area would be substation and HVDC converter station at Spittal, via a • detailed baseline data on land use and environmental 21.5 Hectares. new substation near Thurso (c. 26km). This will replace character and sensitivity, obtained from desk sources and • The tallest structure within the site will be the proposed the existing 132kV OHL between Dounreay and Spittal. site visits; control building which would be of an agricultural type • identification of potential effects, to inform strategies for structure, approx. 35m x 20m x 10m high. • Connection of the new 275 kV OHL to the new 275 kV / enhancing positive outcomes and for avoiding, reducing, • The site would include parking and manoeuvring space 132 kV substation at Dounreay, which is currently under controlling or offsetting potentially undesirable or significant for operation and maintenance of the facility. construction via a different project. negative outcomes; • Existing trees will be retained for screening purposes and • further landscaping will be placed in appropriate places • Construction of the new Thurso South 275 kV / 132 kV / initial consultations with key stakeholders to inform the on site. This will be determined following the landscape 33 kV substation, and associated works to connect the above and the subsequent refinement of the routing study and visual assessment. existing 33kV distribution infrastructure to the new and selection of the preferred substation. • The Preferred Route Mybster Substation Description Connection of the new 275 kV OHL to the new 275kV / 132 kV substation and HVDC converter station at Spittal, which is currently being progressed via a different A preferred route for the proposed reinforcement is shown on project. • The works involve extending the existing 132kV/33KV the front cover of this leaflet. The final, proposed route will be Mybster substation to the north. determined after this detailed consultation and will be subject to • Construction of a new double circuit 132 kV OHL between • A new access will be constructed off the A9. an environmental impact assessment. the new Spittal 275kV / 132 kV substation and HVDC • The footprint of the proposed extension will be converter station, and the existing Mybster substation (c. approximately 3 Hectares. The preferred route has been identified, which on the basis of 4km). This will run in parallel with the existing 132 kV OHL • the route selection process is considered to represent the The height of the perimeter fence will be 2.4m, the between the Spittal substation and the existing Mybster optimum balance of technical, economic and environmental highest 132kV busbar will be approximately 7m and the substation. feasibility. highest 132kV tower 40m. • The site would include adequate parking and • Construction of 132 kV infrastructure at the existing The precise route alignment of the OHL and the location of manoeuvring space for operation and maintenance of the Mybster substation. These works will be adjacent to the facility. north of the existing substation. individual towers will be determined following completion of ongoing detailed surveys to identify engineering, land use or • The control building would be of an agricultural / industrial type structure, approximately 33m x 20m x 7m • Connection of the new 132 kV OHL to the new 275kV / environmental constraints which may require localised modifications to the route. high. 132 kV substation and HVDC converter station at Spittal, and to the new 132 kV infrastructure at the existing Mybster substation. 1 2 3 Consultation Process SSE (Scottish and Southern Energy) Dounreay to Mybster As well as endeavouring to select the best possible route for the Corporate Profile proposed overhead line reinforcement, we want to keep everyone SSE Power Distribution, part of SSE plc, owns and maintains two 275kV / 132kV affected by the proposal informed of our intentions. We firmly electricity networks in the north of Scotland - the electricity believe that early and regular communication and consultation transmission network and the electricity distribution network. In with those likely to be affected by the proposal forms a critical Scotland, SSE Power Distribution comprises two businesses: part of its development. Scottish Hydro Electric Power Distribution PLC (SHEPD) A route for the new overhead lines, shown on the plan above, which operates the high and low voltage electricity network that Caithness Horizons was selected by undertaking a series of studies to determine distributes electricity to around 700,000 customers in northern technical feasibility, economic viability, land use and any mainland Scotland and the Scottish Islands. Thurso environmental constraints. These were then reviewed together to And identify the preferred route that balanced each of these considerations. Scottish Hydro Electric Transmission Limited (SHETL) which 4 July 2012 owns and maintains the 132kV and 275kV electricity transmission As part of the environmental studies we are consulting with the network in the north of Scotland, in some of the UK's most Highland Council, statutory and non-statutory bodies and other challenging terrain. interested parties to collect many types of baseline information One of our principles of responsibility is to ensure the including landscape and visual amenity, nature conservation, communities which we serve have a safe and reliable supply of cultural heritage, archaeology and land use. electricity, and that we ensure we do everything we can to restore supplies as quickly as possible following interruptions. The current programme for the project is shown below: • Identify preferred route for overhead lines Complete Scottish Hydro Electric Transmission Limited • Publish consultation document on overhead lines Complete Electricity networks provide an essential physical link between • Undertake public exhibition for all project elements July 2012 electricity generators and electricity users. As such, the owners of networks have statutory obligations including ensuring that they • Refine the preferred route and select a proposed route July 2012 are able to provide an economic and efficient service to • Complete Environmental Impact Assessment Oct 2012 generators who wish to connect onto their network. • Apply for consents Nov 2012 Electricity transmission businesses like SHETL are natural • Start Construction Early 2014 regional monopolies. As a result, they are regulated by the Gas and Electricity Markets Authority (Ofgem) through a ‘price control’. • Phased completion and commissioning 2015 - 2016 Amongst