Beauly Mossford 132kV Transmission Line Replacement Environmental Statement - Non Technical Summary

Transcription

1 Beauly Mossford 132kV Transmission Line Replacement - Non Technical Summary

2 NON-TECHNICAL SUMMARY 1 INTRODUCTION This (NTS) provides a summary of the information presented in the Beauly Mossford (ES), in respect of the effects on the environment of the proposed Beauly to Mossford replacement 132kV overhead line. Where possible, non-technical information is used in this chapter The proposed project comprises the construction, installation and operation of a replacement 132kV double circuit high voltage overhead electricity transmission line, between Corriemoillie, west of Garve and Dunmore, to the north-west of Beauly. In addition the project includes the dismantling of the two existing single circuit 132kV overhead lines that run between Mossford and Beauly. Figure NTS1 illustrates the route of the replacement overhead line The project also includes proposed stone access tracks to facilitate construction and some sections of lower voltage line diversions that are required in order to meet the requisite safety clearances between overhead lines and a replacement connection with the existing Loch Luichart substation The ES has set out the detail of the need for the project and its characteristics. The ES has considered effects on the land-based environment, encompassing the soils and geology; hydrology and hydrogeology; terrestrial ecology and nature conservation; ornithology; forestry; agricultural and sporting land use; cultural heritage and archaeology; landscape character; visual amenity; access and recreation; construction traffic and transport; carbon budget; other physical effects (including noise and air quality); and planning and committed development. Cumulative effects on the natural environment and on the people of the area have also been considered Assessments have been undertaken in accordance with best practice and approved methodologies and this information is set out within each technical chapter of the ES. Consultations with the relevant statutory organisations and others are referenced. Supporting information is included in Appendices to the ES, with plans and figures illustrating the findings of the assessments, also provided. Page NTS-1

3 2 THE PROJECT AND PROJECT CHARACTERISTICS 2.1 Project need The project is required in order to meet the increased demand by renewable energy generation projects in the Strathconon and Mossford areas to connect to the electricity transmission network. This is in accordance with the wider UK and Scottish Government objectives to provide significant proportions of its energy use from renewable sources The existing transmission infrastructure serving the Mossford area, from Beauly, was constructed in the 1950s to serve a rural area, with low demand for electricity, and to connect the hydro-electric schemes present in this area to the north of Scotland load centres. The capacity of the existing overhead lines allows the connection of around 140MW of generation; SHETL now requires to connect over 250MW of generation to the transmission network The replacement of the existing transmission infrastructure between Beauly and Mossford is therefore required to remove constraints and to enable further connections to the transmission system. 2.2 Project characteristics The proposed project includes the construction / installation and operation of a double circuit 132kV overhead transmission line, on 97 towers, extending over a length of some 26km between Corriemoillie, to the north of Loch Luichart and Dunmore, north-west of Beauly. The lattice steel towers would be an average of 30.6m in height. Figure NTS2 provides illustrations of the existing and proposed lattice steel towers The project also requires the dismantling of the two existing single circuit 132kV overhead lines that run within this area. Much of the replacement line follows the same, or a similar alignment to one or other of the existing overhead lines, though with taller towers. Some new access tracks would be required as part of the construction process and these would remain as permanent features. In addition, some existing 33kV and 11kV overhead distribution lines would require to be diverted, where these conflict with the replacement overhead line. These diversions would occur in the Scatwell / Comrie, Loch Achonachie (southern end) and Orrinside Page NTS-2

4 areas of the project. At Loch Luichart, a replacement connection would be provided to the substation, including three new wood poles in the vicinity of tower BM The starting point for the project is the consented substation at Corriemoillie, to the north of Loch Luichart and west of Garve. The replacement overhead line would run generally east and south to a cable termination compound at Dunmore, to the north west of Beauly, which is to be constructed as part of the wirescape mitigation measures that form a commitment of the Beauly Denny 400kV overhead line Tower spacings would vary depending on topography and the need to span changes in elevation or features such as river crossings. Towers would generally be spaced at between 200m and 350m, though in places towers may require to be closer together (for instance at Auchmore) or further apart (at the Conon Falls and Carn Faire nan Con areas) No borrow pits would be required for this project; stone required for the construction of new or upgrading of existing access tracks would be imported to the site Construction works are anticipated as commencing in early 2013, with completion in late 2014 and reinstatement works finalised in A Construction Environmental Management Document would be produced to control details of working methods and method statements. 3 GEOLOGY AND SOILS The assessment of effects on geology and soils has considered the construction, dismantling and operational stages of the proposed project. The baseline geology and soils position has been defined through identification of the broad geological and soils characteristics for the route of the replacement overhead line. Peat stability issues have also been considered The potential impacts of the proposed project on geology and soils, peat stability and contaminated land have been identified and mitigation measures developed to avoid, reduce or offset these effects. The residual impacts of the proposed project on these aspects, following mitigation, were then assessed. Page NTS-3

5 3.1.3 The proposed overhead line route would result in the disturbance of small areas of peatland (most notably around proposed tower BM4) during tower and access track construction, which cannot be fully mitigated. Residual effects on the peat resource are assessed as negligible to minor adverse Once the construction phase has been completed, there would be no discernable operational effects associated with the soils and geology in the vicinity of the replacement overhead line. 4 HYDROLOGY AND HYDROGEOLOGY The assessment of effects on hydrology and hydrogeology has primarily considered the construction phase, as the operation of the replacement overhead line is not anticipated as giving rise to any significant adverse effects The baseline hydrological and hydrogeological conditions have been assessed and described following desk and site survey work (the latter focussed on locations where construction access tracks would require to cross existing watercourses). The sensitivity of each watercourse, together with relevant ecological data, has been assessed and detailed hydrological data obtained for the key catchments and subcatchments through which the replacement overhead line would pass. Areas of potential groundwater sensitivity and abstraction from ground or surface waters were identified and information obtained in respect of private water supplies in the local area This information was used to determine any potentially significant adverse impacts on the hydrology and hydrogeology of the area. Methods of best practice have been identified at the construction and dismantling stage to prevent potential impacts from the outset. Where this is not possible, mitigation methods have been recommended to reduce, remove or offset the impact. Any residual impacts which would remain after these mitigation measures have been considered have been identified The assessment of residual effects for the proposed overhead line on the hydrology and hydrogeology of the area has identified that there may be some detectable changes in water quality, although these are anticipated to be minor and temporary. As such these would not be significant effects. Page NTS-4

6 5 TERRESTRIAL ECOLOGY AND NATURE CONSERVATION The assessment of effects on the terrestrial ecology and nature conservation interests of the Beauly Mossford area has considered the construction, dismantling and operational stages of the project. The baseline ecology and nature conservation has been defined through identification of the broad characteristics of the study area, together with detailed survey work within a corridor of up to 500m to either side of the route of the replacement overhead line. The sensitivity of habitats and species has been determined with reference to the quality and sensitivity of the baseline features. Plant communities at more sensitive locations along the route have been surveyed using the NVC (National Vegetation Classification) categories. Surveys have also been carried out in respect of protected species that may be present in the area The potential significant adverse impacts of the proposed project on terrestrial ecology and nature conservation were identified and mitigation measures developed to avoid, reduce or offset these. The residual impacts of the project, which would remain after implementation of these mitigation measures, were also identified The assessment concluded that none of the residual effects of the proposed development were considered to be of greater than minor significance, primarily due to the net increase in habitat which would result from the replacement of two overhead single circuit lines with one double circuit line Where minor residual effects have been recorded, these are primarily in association with the construction or dismantling phase of the works, and when combined with the largely beneficial effects of the proposals during the operational phase, such effects are considered to be balanced so as to have only negligible impacts in a worst case scenario The single, major adverse impact of the proposals on terrestrial ecology, prior to the implementation of any mitigation is on badger, through the substantial disturbance to and potential loss of a main sett along the route during the construction phase. This will be mitigated through the retention of the sett, using careful working methods, if possible, or through the creation of a replacement sett prior to the exclusion and demolition of the existing sett, if retention is not possible. Mitigation will therefore ensure that no badgers are harmed by the construction works and the Page NTS-5

7 residual impact is therefore reduced to minor adverse. This species is not considered to be of conservation importance in terms of population numbers, and therefore the residual minor adverse impact resulting from the disturbance of the sett is likely to be readily absorbed by the local population in the long term and is not considered to be significant, in the context of the local badger population Overall it is considered that all of the effects of the proposed development can be readily mitigated to ensure that the impact on terrestrial ecology is minimised. 6 ORNITHOLOGY The assessment of effects on the ornithological interests of the Beauly Mossford area has focussed on the construction, dismantling and operational effects on the key avian receptors (birds of conservation concern and their supporting habitats). Particular consideration has been given to the potential impacts on bird species which are of conservation concern and which are considered vulnerable to adverse impacts from overhead lines The assessment has been undertaken as a combination of desk study and extensive field surveys of the ornithology of the study area, the findings of which are set out in the relevant chapter of the ES and in supporting figures and appendices Field surveys, completed between September 2010 and September 2011, can be summarised as follows: Targeted bird flight activity survey of sections of the replacement overhead line where the route deviates from the existing overhead line from September 2010 to September 2011; Winter woodland bird survey including all potentially suitable habitats within c. 500m of the replacement overhead line route, completed between October 2010 and February 2011; and Various breeding bird surveys including all potentially suitable habitats within c m of the replacement overhead line and associated access tracks completed between March and July The potential for the development to give rise to adverse impacts on nationally and internationally designated areas in the vicinity of the replacement overhead line, has Page NTS-6

8 also been considered. In this regard the assessment has concluded that there would be no potential for appreciable adverse impacts on the qualifying interests of any designated site in the vicinity of the proposals. Therefore in relation to Natura sites (i.e. Special Protection Areas) it has been concluded that there is no requirement to undertake any assessment of the Beauly to Mossford proposals under Regulation 48 of the Habitats Regulations The assessment concluded that there would be the potential for possibly significant adverse impacts on breeding birds as a result of the construction and dismantling operations. This would affect the following species: Red-throated diver, Wildfowl, Red kite, Hen harrier, Goshawk, Golden eagle, Osprey, Peregrine, Black grouse, Waders, Crossbill spp, and other passerines The risk of collision by birds with the replacement overhead line has also been considered as part of the assessment. As this proposal is essentially a replacement and upgrade of an existing section of transmission line, this would have the net effect of replacing two sets of earth wires with a single set in essentially the same location. The proposed towers would be taller than the existing ones (on average c. 7m taller but up to 13m in some instances) and the conductors and earth wire would be larger in diameter than those on the existing overhead lines The replacement of the existing single circuit overhead lines with a double circuit overhead line would significantly reduce the length of earth wires within the study corridor. The earth wire is frequently cited as the most hazardous to birds in flight for typical high voltage overhead line designs in the UK (see discussion above). The diameter of the replacement conductors and earth wire would be greater than those on the existing overhead line, which should increase the visibility of the wires to birds in flight. However, the scale of the beneficial effect here is uncertain and may be expected to be balanced against a reduction in overall visibility of a single line of towers in comparison to two parallel overhead lines and the greater height of the replacement line in comparison to the existing overhead lines There would be fewer watercourse crossings for the replacement overhead line in comparison to the existing infrastructure. The two existing 132kV lines cross significant watercourses a total of six times (12 if each crossing is counted as two). The replacement overhead line would cross a total of five watercourses. This has the potential to reduce the hazard that the replacement overhead line presents to birds Page NTS-7

9 in fight. Flight activity, particularly by birds considered to be of greater susceptibility to collision with overhead lines such as wildfowl, can be concentrated along watercourses For the sections of the replacement overhead line that are built on a new alignment, there would be a relatively short period (estimated to be not longer than 12 months) when both the existing and replacement overhead lines would be in place simultaneously (i.e. the overlap period before the existing line is fully dismantled). The proposed and existing overhead lines run parallel for a relatively large proportion of the length of the route, such that both sets of lines and towers would be in the field of view of birds flying near to either overhead line. Consequently, this is considered unlikely to increase the collision risk as the perceptibility of the overhead lines together would be expected to be higher than where the lines are separated by a greater distance. It is therefore concluded that on the basis that the overlap period would be not more than 12 months, there would be no long-term significant adverse impacts to any receptor as a result of the overlap period Operational phase impacts in terms of habitat loss are assessed as significant for Red kite, only, in the long term, pre-mitigation. The steel lattice towers of the replacement overhead line would provide vantage points for raptors and corvids, and thereby influencing predation risk for some breeding birds, particularly for sections of the line passing over open moorland (e.g. potentially affecting breeding waders and songbirds). However, given the replacement nature of this proposal, and that the actual number of towers would be significantly reduced following dismantling of the existing single circuit 132kV lines, the net effect is considered to be beneficial for all relevant receptors (i.e. moorland songbirds and waders) A range of mitigation measures have been proposed to address the potential significant adverse construction and operation-related impacts on key avian receptors. These include pre-construction surveys; felling of trees / vegetation clearance in advance of the main breeding bird season, or alternatively felling only after the completion of a breeding bird nest survey; the development of exclusion zones from nest sites; and where possible, programming works to avoid starting within the main breeding season In summary, with the implementation of the mitigation measures as proposed, the residual impact of the construction and operation of the replacement overhead line Page NTS-8

10 is considered to be no greater than minor adverse and not significant for any avian receptor. 7 FORESTRY The assessment of effects on forestry has considered the potential significant impacts of the proposed development on the commercial forestry and native woodland areas between Beauly and Mossford The installation of new permanent access tracks in order to construct the replacement overhead line is seen as a beneficial impact, where these are located within areas of forestry. Similarly the releasing of land from redundant wayleaves (as a result of the replacement line occupying one, rather than two corridors through forested or native woodland areas) is also seen as a beneficial impact Significant adverse effects during the construction phase would relate to the felling of native Scots pine (Garve Hill 1); the felling of broadleaves (Garve Hill 3, Scatwell Estate 1, 3 & 4, Strathconon Plantation, Loch Achonachie, Tower Mains, 2 Orrinside, Balno Farm, The Knoll); the felling of productive crops (Scatwell Estate 1, Strathconon Plantation, Rheindown Forest); windblow (Strathconon Plantation, Rheindown Forest); deer fence disruption (Loch Achonachie); and the clearance of young crops (Rheindown Forest) Significant adverse effects of the operational phase of the development are more limited and relate to the sterilisation of productive areas (Strathconon Plantation, Rheindown Forest); the sterilisation of non-productive areas (Garve Hill 3, Scatwell Estate 1, 3 & 4, Loch Achonachie, Tower Mains, 2 Orrinside, Balno Farm); and the loss of native woodland sites (Scatwell Estate 1, Loch Achonachie, Balno Farm) Mitigation measures are proposed to prevent or offset significant adverse effects. Nevertheless some significant adverse residual effects would remain; these comprise: felling of broadleaves, felling of productive crop, windblow, sterilisation of non-productive land, and sterilisation of productive land; and loss of native woodland sites across several woodlands The felling of broadleaves (and the associated sterilisation of non-productive areas and loss of native woodland sites) is off-set over several sites by the recolonisation of redundant wayleaves. Over the entire study area, 24.37ha of land is released from Page NTS-9

11 wayleaves, balanced against 10.71ha of productive land which would be sterilised (and is recorded as a significant effect) and 12.44ha of non-productive land which would be sterilised (and is recorded as a significant effect) It is considered that the natural regeneration of redundant wayleaves would compensate for the sterilised non-productive areas and, theoretically, the productive areas, although for the latter the redundant wayleaves may be unsuitable for compensatory planting for productive forestry. In addition the above figures are the total areas of sterilisation and recolonisation and that there are individual sites that do not benefit from the proposed mitigation. 8 AGRICULTURE AND SPORTING LAND USE The assessment of effects on agriculture and sporting land use has considered the potential impacts of the proposed development on 25 agricultural and sporting land interests. Of these, four are Forestry Commission holdings and the remainder are privately owned land holdings. Four smallholdings with no agricultural or sporting interests were not considered within the assessment The majority of the land crossed by the replacement overhead line falls within Land Capability classes 4, 5 and 6 (classes 5 and 6 being of low capability for agriculture), reflecting the nature of the soil types and topography. Only a small amount of prime agricultural land (Class 3.1) is present on the proposed route The net effect of the construction and dismantling operations is: five fewer land interests affected; two less towers on prime land occupying the same land area; line length reduced by 0.43km over prime agricultural land; 78 fewer towers on non-prime land; footprint on non-prime land reduced by 0.06ha; and line length reduced by 25.39km over non-prime land This is considered to be of moderate beneficial significance when considered for the scheme as a whole. Page NTS-10

12 8.1.5 The project would result in potential effects on agricultural and sporting activity in relation to permanent land loss (replacement tower positions and permanent access tracks), disruption from temporary land loss during construction and dismantling, disruption to normal agricultural and sporting activities arising from the presence of the construction teams, disruption to access during construction and dismantling, potential damage to the agricultural capability of fields and soils from construction/dismantling works and traffic, and disruption to existing field drainage systems Mitigation has been developed to limit the effects of the construction and dismantling of the overhead lines, as far as is practically possible. On completion of the project, there would be no significant adverse residual effects on agriculture and sporting interests. The mitigation measures relate to minimising the disruption to land interests during the construction and dismantling process and during any maintenance, post-construction. They focus on: considerate construction; maintenance of access to land; protection of soil, drainage and boundary feature resources; protection of animal, crop and soil health; and compensation for disruption There would be beneficial effects from the reduction in the number of overhead lines present in this area. The assessment has identified that 92% of the land interests would see a beneficial residual effect as a result of a reduction in overhead line length and the presence of fewer towers within their land holdings. 9 ARCHAEOLOGY AND CULTURAL HERITAGE The assessment of effects on the archaeological and cultural heritage interests of the Beauly Mossford area has been undertaken as a combination of desk study and field survey work. Effects have been considered in relation to the construction and dismantling works, and the operational phase of the project, on the known and unknown archaeological interest of the area. Following mitigation there would be no significant adverse impacts on any such assets All construction impacts on known cultural heritage assets have been assessed as being of minor or negligible significance, following mitigation. Mitigation is specific to the impacts identified but, in general, would comprise a programme of Page NTS-11

13 archaeological works, marking out of known assets and micro-routeing of access tracks / micro-siting of towers In addition, the potential for effects upon the setting of cultural heritage assets has been considered. No significant adverse effects on the setting of cultural heritage assets have been identified. Consequently, no mitigation is proposed in relation to setting impacts It is considered that, following the implementation of the mitigation measures as proposed, there would be no significant adverse residual impacts on the cultural heritage resource of the area. 10 LANDSCAPE CHARACTER The assessment of effects of the proposed development on the landscape character of the area between Beauly and Mossford has considered the potential for adverse effects on the landscape character and landscape resource, including designated areas, on the landscape setting of cultural heritage features, and on the landscape of recreation and tourism features present in the area The majority of significant adverse impacts on landscape character would occur during the construction phase of the project and as such would be short term, temporary effects. No mitigation is proposed in respect of these short term effects. Mitigation is to some extent built into the routeing of the replacement overhead line, in the first instance; in addition, careful tower positioning and consideration of the heights of towers to be used has also been important in ensuring that potential adverse effects on landscape character are minimised, as far as possible. Mitigation is proposed in order to address identified significant adverse impacts in relation to the presence of new permanent access tracks in two locations, on the hillsides to the west of Garve, and to the south of Loch Achonachie; and to address impacts on the landscape character of the Fairburn Garden and Designed Landscape (GDL) There would be beneficial effects on the landscape character at the local level from the reduction in the number of overhead lines and line towers present within the area between Beauly and Mossford. Page NTS-12

14 One significant adverse residual impact would remain: on the landscape setting of the Comrie township (cultural heritage asset) from the presence of the operational replacement overhead line In the longer term, with the implementation of the mitigation measures proposed in the ES, it is considered that residual effects on the overall landscape character of the area would not be significant. 11 VISUAL AMENITY An assessment of effects of the proposed development on the visual amenity of the Beauly Mossford area has been undertaken. This has considered the extent to which the construction, dismantling and operation of the replacement overhead line would adversely affect the visual amenity of residential properties; users of roads and rights of way, and other means of transportation; and users of formal and informal areas of recreation, where these occur in the vicinity of the proposed development The majority of significant adverse effects on visual amenity relate to construction effects arising from the presence of plant and machinery and the permanent new access tracks required for construction of the replacement overhead line. These would generally be short term and temporary effects There would be beneficial effects associated with the removal of two existing overhead lines and their replacement with one double circuit overhead line, albeit on taller towers Significant adverse impacts on visual amenity from the presence of the operational replacement overhead line have been identified in respect of the following: moderate adverse effects on the visual amenity of the Corriemoillie Lodge property (views from upper floor windows of tower BM7); moderate adverse effects on the visual setting of the Gorstan township, from the presence of permanent access tracks (residual effects of minor adverse); moderate adverse effects on the visual setting of the Comrie township; moderate adverse effects on the visual setting of the Fairburn GDL; and moderate adverse effects on the visual amenity of users of the section of path close to the terminal tower BM97. Page NTS-13

15 Mitigation to address significant adverse visual impacts relates to the mitigation proposed in respect of landscape character In the longer term it is considered that, with the implementation of the mitigation measures (landscape and visual) as proposed, impacts on visual amenity would generally be reduced to below significant effects. Moderate adverse impacts would remain in respect of the visual amenity of Corriemoillie Lodge (views from upper storey windows) and effects on the visual setting of the Comrie township (cultural heritage asset) In general, the overall reduction in the number of line towers in the Beauly Mossford area, with the reduction from two overhead lines, to one, would result in beneficial impacts on the visual amenity of the Beauly Mossford area Figures NTS3 and NTS4 are two of the photomontages prepared for the Beauly Mossford ES, and illustrate the proposed replacement overhead line in views from the Little Scatwell and Corry of Ardnagrask areas of the route. 12 ACCESS AND RECREATION The assessment of effects on access and recreation has considered the extent to which the construction, dismantling and operation of the replacement overhead line would adversely affect this aspect of the area. Consideration is also given to tourism facilities present in the immediate vicinity of the replacement overhead line Significant adverse effects are identified for the construction and dismantling operations, only; these would be short term, temporary effects on various paths and rights of way in the vicinity of the proposed route, as follows: right of way HR48, in the area between Garve and the southern end of Lochluichart; a path forming part of the wider access network to the south of Loch Achonachie (between towers BM58 and BM59); two paths forming part of the wider access network in the vicinity of tower BM62 and at BM70-BM71; the general use of the area between Loch Achonachie and Achnasoul for informal recreation; Page NTS-14

16 a Core Path in the Corry of Arnagrask area; and paths forming part of the wider access network at: o o o o o o Achnasoul Wood; Balno; Auchmore; on the east side of Cnoc Croit na Maoile; leading north-west from Corrie Vannie; and leading north-west from the local road at Dunmore / Ruilick No long term closures or diversions are proposed as part of the works, though occasional closures of up to a day may be required in certain areas. Minor diversions may be required where working areas at tower locations extend across paths or tracks, in order to keep the path open. SHETL would ensure that the local communities are kept informed of the project timescales with appropriate notice given, through press adverts, use of community notice boards and discussion with the local community councils. If necessary, liaison will also be undertaken with any organisations likely to be using the area for recreation Mitigation is proposed in order to reduce or remove these adverse effects and includes measures to ensure that construction workers are aware of the likely presence of walkers in specific areas and the implementation of speed limits for construction vehicles, as well as signage to inform the public about the presence of construction operations With the implementation of this mitigation, residual effects are identified as being reduced to minor adverse or negligible. There would be no significant adverse effects associated with the operation of the replacement overhead line The reduction in the number of overhead lines present in this area can be expected to be of some, limited benefit to the use of the area for tourism and for access and recreation, as can the upgrading of existing tracks and provision of new permanent tracks associated with the construction of the replacement overhead line. Page NTS-15

17 13 TRAFFIC AND TRANSPORTATION The assessment of effects on traffic and transportation has focussed on the impacts arising during the construction and dismantling phase of the project. Operational effects on the local and trunk road networks are anticipated as negligible Consultations have been undertaken with The Highland Council and Transport Scotland. In addition, surveys of the relevant transportation routes and access points have been completed. The main potential constraints that would give rise to adverse effects from construction traffic have been identified and mitigation measures developed in order to remove or reduce the effects of these constraints The main impacts relate to the requirement for construction traffic to travel on the single track roads that are a feature of much of the project area; limited visibility at proposed access points, the requirement for construction traffic to cross an existing railway line, the presence of structures with weight restrictions and the limited number of passing places on the construction access routes. These are all matters which will be mitigated Mitigation is proposed through the use of signage, edge strengthening, construction of bellmouths, and video survey to ascertain the pre-construction status of the road network, verge clearance and traffic management (where required), the development of a method statement to define how access across the railway will be obtained, the use of alternative routes for any abnormal loads, and enhancement of signage where required With the implementation of the mitigation measures as proposed, the residual impacts of the proposed development construction traffic on the traffic and transportation aspects of the local area, are considered to be no greater than minor adverse. 14 CARBON BUDGET AND SUSTAINABILITY The development of wind farms in the Strathconon and Mossford areas of the Highland region should contribute to a significant reduction in carbon emissions for the duration of the transmission project life (anticipated as 80 years), acting as a displacement for conventional fossil-derived energy systems. Page NTS-16

18 In the short term, the construction, dismantling and installation of overhead line infrastructure and embedded carbon associated with the proposed Beauly Mossford replacement overhead transmission line, and its principal technologies, would result in a net carbon source. However, this would be offset by the generation of renewable energy over the lifetime of the project and calculation of the carbon payback would ultimately substantiate the need for the project The ES has outlined the discernible practices associated with the construction of the replacement overhead line and associated emissions from this. A number of assumptions were made in respect of the construction practices and these are set out in the relevant chapter of the ES SHETL is committed to the reduction of resources in all of its activities and efficiency and sustainability form part of the core values of the Company. In addition, the procurement procedures used by SHETL require potential construction contractors to be scored in terms of the use of raw materials, energy efficiency, waste minimisation and recycling, amongst others. This procedure would be followed for the construction of the Beauly Mossford replacement overhead line The total estimated greenhouse gas (GHG) emissions arising from the production of materials for and associated activities of the Beauly Mossford replacement overhead line is some 8145tCO 2 e. To provide some context for this figure, a 10MWe wind farm (comprising 5 large turbines) would be capable of offsetting 14,000tCO 2 e per annum through the offset of electricity generated by the UK electricity generation mix The construction of the Beauly to Mossford replacement overhead line would inevitably result in the emission of certain greenhouse gases to the atmosphere. It is assumed that carbon sources such as production, transport and construction emissions are unavoidable in providing the infrastructure to facilitate the replacement overhead line, in support of the renewable energy and electricity generation network. Such activities would also be performed efficiently to assist in the control of carbon emissions A range of mitigation measures are proposed in order to minimise the emissions of greenhouse gases during the construction of the replacement overhead line, relating to the efficient operation of the project and sustainability generally. Page NTS-17

19 15 PHYSICAL EFFECTS The replacement overhead line has been assessed for potential significant adverse effects on noise from construction and dismantling; operational noise; construction air quality; and electric and magnetic fields (EMFs). Construction noise Construction noise level predictions have been presented as a worst case based upon the construction of the overhead line and including the development of access routes, and dismantling works. In practice the predicted worst case noise levels would only occur for short periods of time relevant to key construction activities. For the majority of the construction phase, noise levels at receptors would generally be lower than those assessed The majority of the Beauly Mossford area comprises rural land with low levels of ambient or background noise and this would increase the distances over which construction noise would be audible. This would not necessarily constitute a significant impact, however The assessment identified that significant impacts for static source construction noise in both rural and settlement areas are predicted to be few, although the potential for disturbance in very quiet rural areas is fairly high, particularly for receptors located within m of the activities with higher noise levels. Most activities at distances greater than m from the nearest noise sensitive receptors are unlikely to have the potential for disturbance, even in the quietest areas Noise from vehicle movements on construction access tracks would only be distinct during periods when there were no other construction activities in progress. This would be more noticeable at locations close to the source of the noise, though this would also depend on the existing background noise levels in any given area. Noise sensitive receptors positioned close to the access tracks and nearer to the start of the access tracks would be affected more frequently and over a longer period than others Mitigation measures are proposed to address impacts of construction noise. These will include general good practice in construction in order to keep noise emissions to Page NTS-18

20 a minimum. Temporary screens or barriers will be erected as necessary to shield particularly noisy activities and a number of potentially sensitive receptors are identified as part of the assessment, in this regard. If any complaints are received in relation to construction noise, these will be fully investigated and mitigation agreed to keep construction noise within reasonable limits With the implementation of the various mitigation measures, the assessment has predicted that noise levels would be reduced to within the recommended limits for settlement and some rural areas. However, in rural areas with very low ambient noise levels, it is likely that properties within 50m of construction activities and within 100m of dismantling activities would incur noise levels above the recommended limit of 55dB(A) Therefore there are likely to be residual noise impacts at some locations at certain times during the construction period, however these are likely to be limited to periods of short duration within the contract period (usually less than a few weeks) Whilst such residual impacts can be considered significant in terms of the absolute predicted noise levels involved, in all cases these impacts would be temporary in nature and are not predicted to be at a constant level for the duration of the construction phases. Operational noise Noise is a phenomenon associated with operational overhead lines, both during periods of heavy rain or fog, and also after a prolonged dry spell without rain to wash accumulations of contamination from the conductors (wires). The level of noise is proportional to the operating voltage of the transmission line The proposed reinforced overhead transmission line would operate at the same voltage as the existing lines being replaced. No change is therefore expected to the operational audible noise levels SHETL has sought to minimise acoustic effects by routeing the proposed 132kV overhead transmission line, as far as it is feasible, away from residential properties. In all cases, the proposed overhead transmission line is further from properties than the closest existing overhead transmission line being replaced. Page NTS-19

21 Noise levels experienced by receptors are predicted to be no higher than the existing noise levels of the overhead line. Audible noise levels from the proposed line are therefore unlikely to cause complaints under operational or normal weather conditions. Air quality Construction effects There is the potential for impacts from dust to occur during the construction phase; however, this would be temporary in nature Specific mitigation measures are proposed to ensure that emissions from potential sources of dust or particulates during construction and dismantling are kept to a minimum. These are general construction good practice measures- their employment would ensure that no significant dust impacts occur during this phase of the project. Operational effects The impact on traffic flows on the local road network as a result of the operation of the replacement overhead line would be negligible and therefore no assessment has been made of vehicle exhaust emissions with regards to air quality. Electric and magnetic fields Electric and magnetic fields (EMFs), and the associated electromagnetic forces, are a fundamental part of the physical world. Their sources are electric charges (source of the electric field) and the movement of those charges (source of the magnetic field). Electromagnetic forces are partly responsible for the cohesion of material substances and they mediate all the processes of chemistry, including those of life itself. EMFs occur naturally within the body in association with nerve and muscle activity. People are also exposed to the natural magnetic field of the Earth (to which a magnetic compass responds) and natural electric fields in the atmosphere. Page NTS-20

22 In February 2011, the Department of Energy & Climate Change published a Voluntary Code of Practice 1 for reporting of EMF levels. This project complies with all elements of the Code of Practice In addition, even at worst case conditions, it is not possible for the electric or magnetic fields associated with the replacement overhead line to approach the basic restriction levels set by the Health Protection Agency EMF levels from the replacement overhead line are predicted to be well below basic restriction levels under any operational conditions. 16 PLANNING AND DEVELOPMENT The ES has provided an assessment of the planning policy context for the proposed Beauly Mossford replacement overhead line, together with a review of committed development The planning policy review has identified the various statutory Development Plans (Structure Plan, adopted Local Plans, emerging Local Plans and supplementary guidance) in addition to a wide range of national planning policies and relevant supplementary guidance The project is driven by the requirement to replace the existing transmission infrastructure in the Beauly Mossford area, in order to enable the connection of consented and proposed renewable energy developments, to the grid transmission network. The proposed development has been designed to minimise potentially adverse environmental effects, through making use, wherever possible, of the corridors of the existing overhead lines, with deviations from these in limited locations to benefit the local population and the local environment The ES has considered the potential effects of the project on the environment and on the people of the area between Beauly and Mossford. A detailed assessment of these impacts is provided in the relevant technical chapters of the ES and is crossreferenced as appropriate within the Planning and Development chapter (chapter 19). 1 Power Lines: Demonstrating compliance with EMF public exposure guidelines. A Voluntary Code of Practice. Department of Energy and Climate Change, February Page NTS-21

23 A review of the proposed project in terms of committed development has been undertaken. This largely relates to other SHETL projects located in the study area and consented or proposed wind farm developments in the Corriemoillie and Lochluichart areas. No other developments were identified that might be adversely affected by the proposed Beauly Mossford development and no significant effects were identified in relation to the committed developments, as identified The proposed Beauly Mossford replacement 132kV overhead line can be considered to be in accordance with the relevant aspects of the development plan. There would be only limited significant adverse impacts on the environment and on the people of the area, as identified in the relevant chapters of the ES, and mitigation measures are proposed to address any such significant impacts, the majority of which relate to the construction and dismantling operations required for this project and, as such, would be short term impacts. 17 CUMULATIVE EFFECTS There has been a detailed assessment of the potential for cumulative effects associated with the Beauly Mossford project. This has considered, for each aspect of the environment, the scope for cumulative effects associated with the various SHETL projects and other committed development known to be proposed in this area. Of particular concern in this regard is the proposed Western Isles Connection underground HVDC cables, part of the route of which overlaps with the route of the Beauly Mossford replacement overhead line The assessment of cumulative effects has also separately considered the extent to which the Beauly Mossford project may, of itself, give rise to cumulative effects on the natural environment and on the people of the area The assessment of cumulative effects has used, as its base, the identified residual impacts of the replacement overhead line, post-mitigation, as these would be the effects with the greatest potential for adverse cumulative impacts From the assessments undertaken, it can be concluded that there would only be limited cumulative impacts associated with the development of the replacement overhead transmission line between Beauly and Mossford. Page NTS-22

24 The greatest scope for significant adverse cumulative impacts lies with the development of the Western Isles Connection HVDC cables and converter station, as much of the Beauly Mossford route overlaps with, or is in close proximity to the route of the underground cables Mitigation measures have been developed in order to address potentially significant adverse cumulative impacts associated with the hydrology, terrestrial ecology and forestry aspects of the environment. With the implementation of these measures it is anticipated that there would be no significant adverse cumulative effects on the environment of the area There would be only limited areas within the project where construction operations might be expected to give rise to significant adverse cumulative impacts on the people and property of the area, and on the natural environment. Provided that particular care is taken in these areas, to implement the mitigation measures as set out elsewhere within the ES, it is considered that the scope for significant adverse cumulative impacts would be minimised. 18 CONCLUSIONS The assessment of effects of the proposed Beauly Mossford replacement overhead line has considered the potential effects on the environment and on the people of the area The majority of the significant adverse effects identified within the ES relate to the construction phase of the development and as such, would generally be short term, temporary effects (though the clearance of trees from the route of the replacement overhead line, where this is on a new alignment, and the presence of new construction access tracks, would be permanent effects) Major adverse effects have been identified in relation to construction operations, as follows: Geology and soils from the potential destabilisation of slopes and peat resources. Hydrology from the potential sedimentation of watercourses; erosion and scouring; access tracks acting as a conduit for surface water run off, leading to increased sediment loading of downstream watercourses; potential impacts on Page NTS-23