Agenda THE HIGHLAND COUNCIL 5.6 Item NORTH PLANNING APPLICATIONS COMMITTEE Report PLN/007/17 10 JANUARY 2016 No 16/04775/S36 : Dounreay Tri Limited Development Site 6KM NW of Dounreay Nuclear Research Establishment, Dounreay Report by Area Planning Manager SUMMARY Description : Construction of two offshore wind turbines on a single floating platform, each with an installed capacity of up to 6MW (max rotor tip of 201m and max hub height of 124m above the lowest astronomical tide), installation of export cable and deemed planning permission for erection of onshore electricity substation Recommendation - RAISE NO OBJECTION Ward : Landward Caithness Development category : Major (Application under Section 36 of Electricity Act 1989) Pre-determination hearing : None Reason referred to Committee : Application under S36 of the Electricity Act 1989. 1. PROPOSED DEVELOPMENT AND BACKGROUND 1.1 The Highland Council has been consulted by Marine Scotland on applications submitted to them for: 1. Two Marine Licences pursuant to Section 20 of the Marine (Scotland) Act (the "2010 Act") for the deposit of substances and objects and the construction, alteration or improvements of works within the Scottish Marine Area in relation to the Windfarm; and 2. Consent under Section 36 of the Electricity Act 1989 (the "1989 Act") for the construction and operation of a Generating Station ("Section 36 Consent"); and 3. A Direction Under Section 57 Of The Town And Country Planning (Scotland) Act 1997 (As Amended) That Planning Permission For The Ancillary Onshore Development Be Deemed To Be Granted; and 4. A declaration, pursuant to Section 36A of the Electricity Act to extinguish public rights of navigation so far as they pass through those places within the Scottish Marine Area where the single structure forming part of the offshore Windfarm is to be. 1.2 The proposal incorporates works in the marine and terrestrial (land) area. The Growth and Infrastructure Act 2013 allows for the Scottish Ministers to grant deemed planning permission for onshore elements of offshore electricity generation schemes granted consent under Section 36 of the electricity Act. As such, a separate planning application shall not be submitted to the Highland Council, rather deemed consent for the associated onshore infrastructure shall be sought from the Scottish Ministers as part of the Section 36 application. This report and the Council’s consideration relates only to applications 2 and 3 above. 1.3 The proposal comprises: construction of two offshore wind turbines on a single floating platform. Each turbine has an installed capacity of up to 6MW (max rotor tip of 201m and max hub height of 124m above the lowest astronomical tide). This represents the maximum. 3 options are being considered by the developers, including the aforementioned 6MW turbine - a 4MW with a rotor tip of 185m and 5MW with a rotor tip of 186m. All turbine options have 3 blades are set on a yellow platform base. The offshore site area comprises a 5km x 5km area approximately 6km off the coast of Dounreay. The exact siting of the turbines within this area is not conclusively confirmed in the application. In addition to the actual turbines, the offshore elements include: a floating foundation; mooring clump weight; mooring chain and/or steel lines; drag embedment anchors; and scour protection for the anchors and export cable where necessary. The floating platform will be assembled and installed on the platform at a fabrication port and then towed out with the turbines pre-installed, only requiring hooking up to the mooring lines and export cable. Safety lighting is included on the turbines to aviation and navigation specifications. installation of a single 33kV export cable This will bring power to shore immediately to the west of the Dounreay Restoration Site fence line. Installation of the subsea cable, anchors and mooring lines will take around 3 months. These will be buoyed and will take up a small area of sea space. Two cable landfall options have been submitted and indicative onshore cable corridors to connect to the landfall and substation options to the west of Dounreay and Sandside Bay. This stretch of coastline is dominated by slabbing rocks which makes conventional trenched cable landfall very challenging. Two trenchless landfall options are proposed - horizontal directional drilling or pinning. This will also include a cable joint transition bay, where the offshore and onshore cables are spliced together. Two cable landfall options are identified at this stage as both options present different risks to the developer. The onshore cable will be buried to a depth of approximately 1m, subject to ground conditions and will be installed in a trench along the cable route. It is expected that one cable will be installed in a single trench up to 3m with an associated working corridor of up to 20m. The cable route will not be finalised until a contractor is appointed. The construction period for the cable is estimated at 3 months. deemed planning permission for erection of onshore electricity substation or switchgear The substation is to transfer power to the grid at or near the existing Dounreay substation. Two potential locations for the onshore substation have been submitted, these lie immediately south of the Dounreay/Vulcan compounds, adjacent to the existing Dounreay substation. The turbines will export power at 33kV. The project will require either a switchgear to connect to the distribution network at 33kV or a substation to connect to the transmission network at 132KV. The onshore substation or switchgear will include the electrical equipment required to connect the project to the grid. The entire footprint of the substation/switchgear site is likely to be an area of approximately 50m x50m (0.25ha). The majority of electrical plant should be indoors. The substation building itself will be approximately 30m long, 17.5m wide and up to 8m above finished ground level. External lighting will be used to illuminate the building but this will be intermittent and only when people are on site. Following commissioning, it is assumed that the onshore substation will operate continuously (24 hours a day, 7 days a week) except during planned shutdowns for maintenance. The onshore substation will be designed to remain in situ during the life of the wind farm, which is envisaged to be up to 25 years. The substation site will be accessed via an existing access from the A836 which was installed during the upgrade of the Dounreay-Mybster Line in 2015. The construction period for the substation is 12-18 months. Laydown area For the construction of the onshore cable and its landfall, substation and if required, a horizontal directional drilling compound. It is proposed to make use of an existing area of hardstanding which was used during the construction of the existing Dounreay substation in 2013. Decommissioning proposals as the lifetime of the development is expected to be 25 years. 1.4 The Highland Council is an important consultee and views are sought regarding specifics of the proposal as outlined above, including the type and siting and design of the turbines within the identified envelope, the cable route and the siting, design and external appearance of the substation/switchgear. 1.5 The turbines are a demonstration project with two key objectives which are set out in the supporting information submitted by the applicant: 1. to test the performance of a multi turbine floating wind platform in a real offshore environment and use these results to refine the platform for larger scale projects overseas 2. Verification of the economic return to provide a base for more realistic estimations for utility scale projects overseas. The development has an expected operational life of 25 years. 1.6 The applicant has undertaken a site selection exercise to identify this site and has undertaken consultation including a stakeholder drop in session held on 2 February 2016 at Caithness Horizons, Thurso and a public consultation event on 9 April 2016, also at Caithness Horizons, Thurso. A report of public consultation is included in the ES. 1.7 An Environmental Statement has been submitted. The assessment process makes use of the design envelope, an approach to assessment applied where the final design cannot be confirmed ahead of the determination of the application and a level of flexibility is required. The Environmental Statement (ES) therefore sets maximum and minimum turbine dimesons against which the proposal is assessed, as outlined above. It also provides an envelope for the siting of the turbines in the sea. The ES is based on the realistic worse case scenario. The ES defines impacts and effects and cumulative impacts. It also covers: physical and coastal processes; intertidal ecology; benthic and shellfish ecology; fish ecology; marine mammals, turtles and basking sharks; marine ornithology; commercial fisheries; shipping and navigation; aviation and radar; archaeology and cultural heritage; other users of the marine environment; marine renewable energy activities; military activities; subsea cables and utilities; socio-economic; recreation and tourism; geology and hydrology; land use, agriculture and soils; terrestrial ornithology terrestrial ecology; onshore archaeology and cultural heritage; air quality; seascape, landscape and visual amenity. 1.8 It is considered that Marine Scotland is more appropriately placed to come to a view on the acceptability or otherwise of effects on the marine environment and ecology. This report notes all technical consultation responses and representations received but is principally concerned with assessment of the onshore aspects from a land use planning perspective. 1.9 Variations: None 2.0 SITE DESCRIPTION 2.1 The offshore site is located approximately 6km of the coast of Dounreay Nuclear Research Establishment. The site comprises an area of 5km x 5km, it is proposed to site the turbines within this envelope. 2.2 A 0.25ha site area is identified for the onshore elements.