EHG6384 - DBA and walkover survey - proposed Battery Energy Storage Sytem (BESS), Spittal

An archaeological desk-based assessment and walkover survey were undertaken by Royal HaskoningDHV in relation to the construction and operation of a Battery Energy Storage System (BESS) on land located to the south of the existing Spittal 275 kV substation in Spittal, approximately 450m northwest of Spittal Mains Farm, Caithness. The study also included a Scheduled Monument setting assessment. The Proposed Development principally comprises a battery energy storage system (BESS) with a capacity of up to 300 megawatts (MW) which will charge and discharge electricity from the adjacent Spittal 275 kV substation. The walkover survey was carried out on 21st February 2024 to determine the topography of the development footprint and existing land use, the nature of the existing visible heritage assets (e.g. structures and earthworks), and assess factors which may have affected the survival or condition of any known or potential heritage assets. the walkover survey did not identify any further evidence of extant, previously unrecorded heritage assets within the area to be developed. The visit extended beyond the development footprint boundaries for the purposes of scoping designated heritage assets and their intervisibility with the development footprint for the settings assessment. In the absence of any previously recorded heritage assets within the proposed development area, it was considerded that there would be no physical effects on any previously recorded archaeological remains. Any groundworks within the proposed development are would have the potential to adversely impact unknown heritage assets of local to regional value and of low to medium importance. Though unlikely, it should be considered that burials may exist outwith the designated area associated with St Magnus’ Church, burial ground and hospital (SM5413) and could, as a worst case, be of equivalent value, although it was not expected that significant structural remains might extend into the development footprint. Given the presence of Prehistoric remains in the wider area, some of which were Scheduled Monuments, there was a possibility that sub-surface Prehistoric remains existed within the development footprint, though this possibility was expected to be low as no archaeological features were identified during previous ground investigations in 2022 (see EHG5994). No surface earthworks suggestive of archaeological remains were present, and any archaeological remains within the development footprint were likely to be very shallow and to have been significantly disturbed by agricultural activities. Similarly, the survival of archaeological remains within the route of the underground cable connection into Spittal substation was expected to be limited, as the ground here would be heavily disturbed, or artificial, as a result of construction of the existing substation. As a worst-case scenario, which included the use of the existing access track adjacent to St Magnus’ Church for construction traffic, there would likely be a very limited potential for inadvertent disturbance (e.g. vehicle leaving the road) for a short period. However, this could be suitably mitigated using acceptable demarcation (e.g. signage) of the scheduled area, and it was determined during the walkover that the dike separating the track from the scheduled monument would prevent inadvertent harm. Furthermore, any groundworks associated with the proposed development have the potential to adversely impact any unknown heritage assets buried beneath the surface. In this case, a detailed programme of archaeological works proportionate to the nature of the remains identified, would be required in order to mitigate impacts to below ground archaeological remains. It was considered that the embedded mitigation measures presented an effective mitigation for any adverse effects on the setting of St Magnus Church and as such no further mitigation measures were recommended. <1>