Overview of Transmission Projects
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www.ssen-transmission.co.uk/projects/orkney Who we are We are Scottish and Southern Electricity Networks, operating under license as Scottish Hydro Electric Transmission plc (SHE Transmission) for the transmission of electricity in the north of Scotland. What is the difference between Transmission and Distribution? Electricity Transmission is the transportation of electricity from generating plants to where it is required at centres of demand. The Electricity Transmission network, or grid, transports electricity at very high voltages through overhead lines, underground cables and subsea cables. The transmission network connects large scale generation, primarily renewables, to central and southern Scotland and the rest of Great Britain. It also helps secure supply by providing reliable connection to the wider network of generation plans. The Electricity Distribution network is connected into the Transmission network but the voltage is lowered by transformers at electricity substations, and the power is then distributed to homes and businesses through overhead lines or underground cables. Overview of Transmission projects In total we maintain about 5,000km of overhead lines and underground cables – easily enough to stretch across the Atlantic from John O’Groats all the way to Boston in the USA. Our network crosses some of the UK’s most challenging terrain – including circuits that are buried under the seabed, are located over 750m above sea level and up to 250km 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 a high demand to connect from new wind, hydro and marine generators which rely on Scottish and Southern Electricity Networks to provide a physical link between the new sources of power and electricity users. Scottish and Southern Electricity Networks is delivering a major programme of investment to ensure that the network is ready to meet the needs of our customers in the future. Our responsibilities We have a licence for the transmission of electricity in the north of Scotland and we are closely regulated by the energy regulator Ofgem. Our licence stipulates that we must develop and maintain an efficient, co-ordinated and economical system of electricity transmission. Orkney Infrastructure Project Public Consultation April/May 2018 www.ssen-transmission.co.uk/projects/orkney Existing network in Orkney There is currently no transmission infrastructure on the Orkney Islands. The electricity network on Orkney is connected via two distribution subsea cables between Rackwick Bay on Hoy, and Murkle Bay near Thurso. These cables were installed in 1982 and 1998 with a total import/ export capacity of 40MW. Demand on the islands varies between 7MW in summer and 46MW in winter. The current connected embedded generation in Orkney exceeds the capacity of the existing 33kV cables and no further generation can connect to the system at this time. Why reinforcement is required At present, the current level of contracted generation between National Grid (the System Operator) and developers is for a minimum of 220MW of new generation by 2022. To connect this level of generation, a transmission connection is needed between Orkney and the Scottish mainland. An alternative and innovative approach The current regulatory framework requires capacity to be allocated in chronological order based on respective developers contracted position. To proceed with a transmission connection first requires regulatory approval from Ofgem, which in turn requires those contracted developers to demonstrate commitment to their projects. Due to a number of factors over recent years, such as changes in government policy or the readiness of renewable energy projects across Orkney to progress, it has not been possible to proceed with the transmission connection proposal to date. To try and overcome this impasse and help Orkney realise its vast renewables potential, we are considering an alternative approach to allocate the necessary volume of capacity that is required to underpin the case for the proposed 220MW connection. This approach would see capacity allocated on a ready to connect basis, whereby those developers who are ready to commit to their projects would be allocated capacity. This innovative approach, the first of its kind in GB, would first require approval from the energy regulator, Ofgem. An initial consultation on the principles of the proposed alternative approach took place in February and March 2018, with a follow up consultation planned for the summer. Orkney Infrastructure Project Public Consultation April/May 2018 www.ssen-transmission.co.uk/projects/orkney Our proposed solution Orkney to Mainland Scotland Transmission Connection In order to provide a transmission connection that will facilitate the connection of renewable generation, a marine cable linking Mainland Orkney and Mainland Scotland will be required. The new link would provide an additional 220MW of capacity. The main elements of this projects are as follows: • A new substation at Finstown; • An underground cable linking Finstown substation to a cable landing site west of Stromness; • A marine cable linking Mainland Orkney and Caithness; • A new cable route between the Dounreay marine cable landing point and the new substation at Dounreay; and • Construction of a new substation at Dounreay. Public Consultation took place in November 2017 regarding the above elements, further consultation will take place in Summer 2018. Orkney Infrastructure Project To facilitate the connection of new renewable generation At a previous Public Consultation in February 2017, SSEN across Orkney will require the construction of new presented initial proposals for potential routes from Orkney transmission infrastructure. To provide the most efficient and to the Scottish mainland and connections within Orkney. economical solution for the network we are proposing to Following that Consultation SSEN reviewed the feedback connect renewable generators to a central point within the provided and began working on potential routes to connect Orkney mainland at our proposed main substation location at the new generation on Orkney. Finstown. This will maximise the opportunity for generators across Orkney to connect to the transmission network. The routes being considered are to connect the 132kV infrastructure at the generation developments to Finstown The System Operator has accepted several transmission owner substation. The process for selecting a preferred route is construction offers, to connect various renewable generation based on identifying as direct a route as possible ensuring it is developments. To unlock the renewable potential inherent in technically feasible and economic whilst minimizing impacts the Orkney Islands, this infrastructure project would need to on the environment. be undertaken. The purpose of this Consultation is to present our proposal The aim of the project is to design, construct and install 132kV for preferred routes from the contracted generation sites to Transmission infrastructure which will enable access to the Finstown substation. We welcome the opportunity to listen to electricity network for new generation. your views on all the route options presented as this will aid in the next stage of design. The main components of the project are: A second Consultation will take place in late summer 2018, • Construction and installation of 132kV trident our design will be further refined and we will confirm the type wood pole overhead lines and 132kV cables; of infrastructure to be installed based on further technical and • Installation of 132kV subsea cables; environmental analysis and the feedback considered through • Construction and installation of 132kV substation this consultation. Following the Consultation in late summer switchgear at each developer’s substation we will begin to prepare our consent applications to the and Finstown substation; and Scottish Government, Orkney Island Council and Marine • 2 Switching Stations. Scotland as required. Orkney Infrastructure Project Public Consultation April/May 2018 www.ssen-transmission.co.uk/projects/orkney The Routeing Process SHE Transmission’s approach to identifying where a new overhead power line is to be located follows the four stages illustrated below. This project is currently at Stage 3 - Route Selection. Each stage in the process is iterative, increasing in detail and resolution to find the best Routeing Strategy balance of economic, technical and environmental considerations. This staged process Stage 1 Approx Width leads to the eventual identification of a proposed alignment to be taken to consent application stage. Corridor Selection 2 km Stage 2 The objective of Stage 3 is to identify a ‘preferred route’ within the preferred corridor for further appraisal and consultation. Routes are typically between 500m to 1km wide, Route Selection although they may be narrower / wider in specific locations in response to 1 km Stage 3 certain constraints. Alignment Selection During Stage 3 the engineering, land and environmental teams systematically evaluate a Stage 4 20 m variety of route options. The preferred route is the option considered to present the best opportunity to achieve an economically viable, technically feasible and environmentally Consent Application acceptable alignment for consent application. Orkney Infrastructure Project Public Consultation April/May 2018 www.ssen-transmission.co.uk/projects/orkney Route