Helping to secure a Renewable Future: Scottish Hydro Electric Transmission Limited Orkney Caithness Connection - 132kV Scottish Hydro Electric Transmission Limited (SHETL) is part of SSE plc and is the transmission licence holder in the north of Scotland. SHETL has a duty, under Section 9 of the
Electricity Act 1989, to facilitate competition in the generation and supply of electricity. The company also has obligations to offer non-discriminatory terms for connection to the transmission system, both for new generation and for new sources of electricity demand.
Where we are required to extend, upgrade or reinforce our transmission network, we must find an environmentally appropriate, technically feasible and economically viable
solution. We believe that our proposals for the Orkney to Caithness connection fall within these requirements.
Indicative Timeline for Marine Generation
Background
In March 2010 The Crown Estate announced the leased option areas for the Pentland Firth and Orkney Waters Round 1 Development Sites for marine generation totalling a potential 1600MW. This includes a generation potential of up to 1050MW (wave and tidal) around the Orkney isles and 550MW off the Caithness coast. The figure above shows the overall potential of the Pentland Firth and Orkney waters combined. Renewable Energy Infrastructure
Initial forecasts suggest the earliest developments will start in 2014, growing thereafter up to the full As this project is being developed to help facilitate a capacity potential by 2020, assuming successful proving of the technology in the early years. connection to the electricity network for marine generators, there will be associated infrastructure required to connect the The amount of renewable generation that can be exported from Orkney is limited by the capacity of the generation sites to the Orkney substation. This work is the two existing 33kV subsea cables that connect Orkney to the mainland transmission grid at Thurso. responsibility of each developer respectively and subject to Taking account of the renewable generation that has already been connected or is contracted to be various consenting regimes. connected on Orkney, the existing subsea connection has now reached full capacity. This associated infrastructure could include: As a result, new transmission infrastructure is required between Orkney and Caithness. This will need to Submarine cables/ pipe work connect into the existing substation at Dounreay which is currently being upgraded to accommodate a Landfalls number of proposed connections from this project and other developments. A new substation will also be Land based infrastructure required on the west coast of mainland Orkney to facilitate the connection of the marine generation sites Land based connections (underground/ overhead) to the network. Whilst we are not responsible for this associated infrastructure, The proposed 132kV Orkney Caithness Connection is being developed to enable the prompt connection the choice of our substation site and cable route on Orkney of marine renewable energy generation developments off the west coast of Orkney to the wider has considered these requirements at a high level to ensure transmission network at Dounreay in Caithness. It is likely that should the development of the tidal and that this project provides a connection that is fit for purpose wave renewable generators be successful, then further capacity would be required and allowances have and meets the requirement of those wishing to connect. been made for future expansion of the Orkney substation site.
Summary of Generation Activity in Pentland Firth and Orkney Water – Round 1 Development
Potential Project Owner(s) of Tenant Wave/ Potential Connection Tidal Generation to Scheme Costa Head SSE Renewables Developments (UK) Ltd Wave 200MW ✓ Brough Head Aquamarine Power Ltd & SSE Renewables Holdings (UK) Ltd Wave 200MW ✓ Marwick head Scottish Power Renewable UK Ltd Wave 50MW ✓ West Orkney Middle E.ON Climate & Renewables UK Ltd Wave 50MW ✓ South West Orkney South E.ON Climate & Renewables UK Ltd Wave 50MW ✓ Westray South SSE Renewables Developments (UK) Ltd Tidal 200WM ✓ Farr Point Pelamis Wave Power Limited Wave 50MW Cantick Head SSE Renewables Holdings (UK) Ltd & OpenHydro Site Tidal 200MW Development Ltd Inner Sound MeyGen Ltd Tidal 400MW Ness of Duncansby Scottish Power Renewable UK Ltd Tidal 100MW Brough Ness Marine Current Turbines Limited Tidal 100MW TOTAL 1.6GW 750MW
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Project Description - Phased Connections
The project requires the construction of a new subsea cable between Orkney and The current scope of works is to develop Phase 1 with due regard to the potential Caithness to transfer electricity from the marine generators situated off the west development of Phase 2 in the future. coast of the mainland of Orkney to Caithness. The project may consist of two phases: The visualisations below are indicative only, and are presented to show the extents of the Phase 1 substation development in context to the future Phase 2 converter Phase 1 - 132kV AC connection to Caithness station development. Phase 2 - HVDC connection to Peterhead
Phase 1 - by 2015/2016 Phase 2 - by 2020/2021
Phase 1 will provide enough capacity to enable the marine developers to test and Phase 2 will be required if there is sufficient demand from the marine developers for develop the technology but will not provide enough long term capacity for the full capacity above that provided by Phase 1. The projected generation capacity for potential of the leased areas. It will consist of: marine renewables off the west coast of Orkney exceeds that which can be transferred economically by traditional AC (Alternating Current) technology and will Construction of a new 132kV AC (Alternating Current) enclosed substation on require a High Voltage Direct Current (HVDC) technology. Phase 2 will consist of: the west coast of Orkney Mainland to provide a connection point for the marine developers. Construction of a new HVDC Converter station (converts the AC power to DC) Installation of a new 132kV buried cable from the substation to a landfall point on adjacent to Phase 1 132kV substation. the west coast of Orkney Mainland. Installation of a new DC buried cable from the converter station to a landfall point A landfall on Orkney – to be: on the west coast of Orkney Mainland. Directional drill Landfall on Orkney – to be either: Install a 132kV subsea cable between Orkney and Caithness. Directional drill, or A landfall in Caithness close to Dounreay - to be either: Traditional cable landfall in a natural bay. Directional drill, or Install a DC subsea cable between Orkney and Caithness. Traditional cable landfall in a natural inlet. Landfall in Caithness close to Dounreay to be either: Install a new buried 132kV cable from Caithness landfall to the existing Directional drill, or Dounreay substation. Traditional cable landfall in a natural bay Install a new buried DC cable from Caithness landfall to a proposed new HVDC switching station in Caithness. Install a new buried/subsea cable from Caithness switching station to Peterhead.
Indicative Visualisations of Substation at Site E Indicative Visualisations of Substation and Converter station (Phase 1 development) at Site E (Phase 1 and 2 development)
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Overview Project Map - Phase 1 The Development Process
Given the geographical location of the connection applications, the only viable option for the new infrastructure will be the installation of a subsea cable from the west coast of mainland Orkney to Caithness. There will be a requirement for on-land infrastructure to connect the subsea cable to the proposed substation in Orkney and the existing substation at Dounreay. It is appropriate that these connections would be made using underground cables given the anticipated proximity of the landfall to the substation.
Our approach is to develop and explore a range of substation sites, landfall locations, and potential route corridors, in an environmentally- led manner, in order to select a ‘preferred overall option’ for the connection. To do this the project was broken down into four component parts:
Substation site in Orkney, Landfall sites (both on Orkney and Caithness), On land cable routes (both on Orkney and Caithness), and Subsea cable routes
Initially, possible substation sites were identified on the west coast of mainland Orkney as this component of the project was seen to be critical in respect to the operational requirements of the scheme but also due to the known sensitivities surrounding any large scale development in this locality within Orkney.
Following identification of possible substation sites, landfall site options were considered for both Orkney and Caithness followed by the land and subsea cable route options between the possible landfall sites.
Individual studies were undertaken for each component part of the project to identify the environmental, technical and economic implications of the various route and site options as applicable. These were then reviewed together to identify a ‘preferred overall option’ that balanced these environmental, technical and economic implications across all project components.
Project Timescales
One developer has already signed up, with two quotations pending. The current indicative programme is shown below for Phase 1 of the project. Phase 2 of the programme is entirely dependent on the other developers accepting their connection quotes.
Option Selection Process Phase 1 - 132kV AC connection to Caithness 2010 - 2015/2016
Developer Connection Application received December 2010 Further to earlier consultation, economic assessments, technical reports and environmental studies, and in consultation with statutory and non-statutory consultees, renewable developers Compare site/route option September 2011 and landowners, we have developed a preferred solution for the proposed 132kV AC connection. Identify preferred site/route October 2011
Publish consultation document October 2011 Following the first stage of consultation in March 2011, we have undertaken studies and surveys Receive consultation responses December 2011 with subsequent reports prepared on: Orkney and Caithness landfall options (both traditional and direct drilling options); Identify proposed site/route February 2012 terrestrial cable route options; Issue informal scoping request April 2011 subsea cable route options; and Environmental Assessment August 2012 a substation site selection report. Apply for consents August 2012
The findings of the reports and the development of the ‘overall preferred option’ are presented in Start Construction July 2013 the publicly available consultation document. Where a clear preference has not yet been Commissioning Late 2015/2016 identified, alternatives have also been suggested. Following consideration of the consultation responses and findings of further surveys a decision will be made on which option to proceed with. Phase 2 - HVDC connection to Peterhead 2018 - 2020/2021
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Preferred Substation Site Selection Preferred Substation Site
Earlier this year we identified 8 possible sites for the substation. These were selected through a process of high level screening giving due consideration to technical feasibility, proximity to the generators seeking connection, cost and known environmental constraints.
Initial discussions were held with Orkney Islands Council, Scottish Natural Heritage, the Scottish Environment Protection Agency, Historic Scotland and RSPB, to gain a greater understanding of the key factors likely to influence development at each site. These discussions, as well as further communication with the generators themselves led us to reduce the 8 initial site options to 4, which were taken forward for further consideration.
Environmental and technical studies were undertaken on the four substation site options which, along with comments from consultation, were fed into a detailed site selection assessment process. Landscape modelling was also undertaken of the four sites looking at visual impacts of the proposals on sensitive receptors.
Environmental aspects which were considered alongside technical and economic considerations in relation to the substation site options included:
Geology and Soils, Hydrology, Habitats, Protected Species, Ornithology, Cultural Heritage (archaeology), Landscape Character, Visual Amenity, Lands Use, and Access and Recreation.
Of the four sites B, D, and F are believed, on balance, to have a greater number of significant issues that would be hard to satisfactorily overcome as part of the detailed design (including acquiring consent). The preferred option being put forward to this round of consultation is therefore substation Site E.
Visualisation of Substation and Converter station at Site E (Phase 1 and 2 development)
Underground Cables
All land based connections as part of this project in Orkney and Caithness are currently proposed to be buried cables. Your Feedback
A review of the potential landfall options along with the potential We will feedback all comments made as a result of the consultation document or this public underground cable routes was undertaken for each of the four exhibition. Following consultation and further environmental studies an ‘overall proposed option’ substation sites considered. Additionally the cable route options were will be selected for which consent applications will be made. No decisions will be made until full reviewed for the connection to Dounreay substation from potential consideration has been given to the comments, views and suggestions provided by statutory and landfall options along the Caithness coast. key consultees, elected representatives, communities likely to be effected by the proposals and
any other interested parties. Copies of the full Consultation Document are available for public Along with consultation exercises these studies helped identify any consultation at Council offices in Thurso, Wick, Kirkwall and Stromness. The document is also significant issues associated with potential cable routes which may available on the SHETL website, at www.sse.com/OrkneyCaithness. have a bearing on the overall preferred option, for example the relative location of designated sites or archaeology. This exhibition is your opportunity to comment on and ask questions about our proposals so far.
We would greatly appreciate it if you would take the time to fill out our short questionnaire and post In absence of any major constraints the connecting cable route it in the comments box. Alternatively, you can write to: associated with the preferred substation site E is determined by the chosen cable landfall option, and on Caithness the cable route is also Lisa Kelly largely determined by the choice of the preferred or alternative Scottish Hydro Electric Transmission Limited landfall location options. 10 Henderson Road Inverness, IV1 1SN
Email:[email protected]
It would be helpful to receive your comments by 2nd December 2011.
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Substation Site in Detail
A substation is required in order to enable the marine developments to connect to the The overall footprint size will be subject to review and detailed design whereupon transmission network. As the substation on Orkney will be in close proximity to the the intention would be to reduce the size. The site would be surrounded by a 2.5m coast, there is a requirement to house the equipment within a building. This will high security fence of palisade construction and be fitted with a CCTV system. protect the equipment from possible corrosion caused by salt in the atmosphere. The Illumination will be provided internally to allow safe working on the installation with building or buildings would generally be of similar appearance to large agricultural limited lighting at access points to allow safe access to the compound and building. sheds, based on a steel portal frame with industrial cladding on the exterior.
The visualisations shown below represent the infrastructure associated with The development on Orkney was originally proposed as a substation utilising air Phase 1 (132kV Substation) and Phase 2 (HVDC Converter station) developments. insulated switchgear (AIS), but due to sequential increases in the number of 132kV connections required in the design, it became apparent that gas insulated switchgear (GIS) was a more attractive alternative. GIS switch gear provides a more compact building with a smaller foot print.
Substation Site E - Converter Station and Substation Visualisation
1 - View from Choldertou 2 - View from Vestra Fiold
3 - View from Fairview junction 4 - View from Skara Brae
Orkney Cable Landfall Caithness Cable Landfall
A review of potential landfall sites along the west coast of Orkney (from North of Both Melvich Bay and Sandside Bay in Caithness, identified as open cut landfall Birsay Bay to South of Borwick) was undertaken along side the substation site options, have key constraints in relation to environmentally designated sites. The selection process. subsequent underground cable routes for both of these sites also have specific constraints confirming that they are not the preferred option. The landfall study for Orkney identified a number of sites that could be accessed by cable route from substation site E including two open cut sites (Marwick Bay and Further to issues being identified with these open cut landfall options, the preferred Birsay Bay) and three possible areas for directional drilling (North Vestra Fiold, South Caithness landfall option is to directional drill through the cliffs to the north east of Vestra Fiold and North Skaill). Dounreay. There are however alternative Caithness landfall options presented on which comments are welcomed. As substation site E is located immediately adjacent to the South Vestra Fiold directional drill location and this landfall area is assessed as ‘good’, South Vestra Fiold, when assessed in combination with the other project components, would be the preferred landfall option for Orkney. This would eliminate any requirement for an underground cable corridor along the Orkney coastline, reducing any associated environmental impact and additional cost implications.
As both North Vestra Fiold and North Skaill are still classified as ‘very good’ and ‘good’ respectively, these are highlighted as possible alternatives to which comments are welcomed in this consultation process.
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Preferred Option - Orkney Preferred Option - Caithness
Orkney substation (Site E) connection options Cable route options were identified between the possible landfall sites. Some substation sites had a number of route options identified to the potential landfall areas. To simplify the comparison process and aid the selection of a ‘preferred overall option’, where more than one route was originally identified, only the route with the least technical and environmental sensitivities are represented on the presented figures.
Dounreay substation connection options Cable route options were identified between the Dounreay substation and the possible landfall sites/areas. On assessing the route options between Dounreay substation and the various landfall options on the grounds of technical and environmental considerations it became clear that the routes to the west had significantly greater constraints to the cable route heading eastward.
Preferred Option - Subsea cable route
Route options avoiding constraints were derived on a At the north and south of the three principle subsea Following identification of the indicative proposed plan. These route options showed sections and points routes, various connections options have been identified route, a detailed cable route survey will be carried out of convergence. depending on the landfall site chosen. to determine the suitability of the route. The subsea cable would preferably be a single cable with three The subsea cable route options were then assessed It is clear from the assessment in the subsea cable cores (one for each ‘phase’) including fibre optic using environmental and technical criteria. These have route selection study that routes to the southern landfall communication for control purposes within the cable. provided a classification for each section of route site options in Orkney and eastern landfall site options ranging from ‘Poor’ to ‘Very good’. Through assessment in Caithness are preferred. The required spacing between marine cable circuits is of the option classification, costs and in consultation in direct relation to the depth of the water and in with consultees (e.g. renewable developers), the route general should be three times the water depth, to options were developed into a preferred route. ensure adequate distance for retrieval at a later stage.
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