§1.3 Appropriate assessment of a national electricity programme in Ireland – assessment of cumulative effects

The Grid25 Implementation Programme (the IP) is a plan for the development of the electricity network in Ireland until 2025. It aims to ensure a long-term sustainable and reliable supply from renewable and conventional sources to the cities, towns, villages, homes and other key markets where the power is required. The main provisions of the IP until 2025 include: — upgrading 2 530 km of the existing network and — building 828 km of new infrastructure. As a high-level strategy, the Grid25 IP, provides an indication of the types of infrastructural requirements likely to arise in the future, given government policy on renewable energy and predicted growth in demand, but does not prescribe exactly the location of infrastructure such as generation plants or transformers, or the route of transmission lines. Instead, it provides an indicative overview of the general approach proposed for the future development of the grid. The programme has been subject to an appropriate assessment according to Article 6(3) of the Habitats Directive. As the IP applies to the entire Republic of Ireland and may have synergistic effects beyond Ireland’s borders, a screening exercise was carried out on all Natura 2000 sites within the Republic and Northern Ireland. A preliminary examination of the types of effects that may arise as a result of the IP was carried out. The type of impact depends on the type of infrastructure constructed, including: — Site based infrastructure e.g. electricity generating stations, transformers, etc. — Linear infrastructure e.g. overhead lines, underground cables. Impacts that could potentially occur through the implementation of the IP were categorised under a number of headings: — loss/reduction of habitat area; — disturbance to key species; — habitat type or species habitat fragmentation; — reduction in species density; — changes in key indicators of conservation value such as decrease in water quality and quantity. Due to the nature of the IP, impacts were described in a general manner but were specifically identified for any of the sites that were screened in. The screening process identified approximately 340 SACs and 97 SPAs that could potentially be either directly or indirectly impacted through the development of infrastructure proposed by the IP. A further 18 SACs and 2 SPAs in Northern Ireland may be affected by cross border interconnectors. The appropriate assessment then considered the potential adverse effects occurring as a result of the application of the IP alone or in-combination with other plans, programmes and/or projects. The assessment of cumulative impacts was firstly addressed in order to make sure that they were properly considered when assessing the potential significant effects of the IP. Assessment of cumulative effects The assessment identified the principal plans, policies and programmes (at national, regional and county level) that are likely to give rise to developments causing effects that could combine or interact with those of the IP for Grid25. This analysis required knowledge of the likely effects of all plans/developments under consideration, and despite the limitations in the information about the likely effects of some plans, it could identify the interactions resulting in cumulative impacts for some plans. A few examples are provided in then table below. Policy, plan, programme or projects Interactions resulting in cumulative impacts National (example) Transport 21 Programme Potential in-combination impacts may arise where new or upgraded transport corridors are constructed in line with new or upgraded transmission infrastructure. Impacts may include the following: — Habitat loss and disturbance. All terrestrial based designated sites may be affected, depending on where infrastructure and transmission lines are located/routed. — Alterations to local hydrology and effect on adjacent habitats. Groundwater dependant habitats such as fens, turloughs and bogs are most likely to be affected. — Sediment pollution and associated hydrological impacts where surface water dependant species and habitats are affected. Salmon, lamprey, white clawed crayfish and freshwater pearl mussel may potentially be affected. — Contamination of surface and groundwater with pollutants (e.g. fuels, lubricants, concrete) during construction. Salmon, lamprey, white clawed crayfish and freshwater pearl mussel may potentially be affected. — Disturbance of species during construction and maintenance activities. Species that may be affected include nesting and overwintering birds in coastal and freshwater SPAs; otters and kingfishers, where development occurs adjacent to or crossing watercourses; bats, where development affects woodlands, hedgerows or roosting sites. — Risk of bird strike where overhead transmission cables are installed near SPAs or across bird flight lines. Regional (example) Regional waste management plans Potential in-combination impacts may arise where new waste infrastructure and new transmission infrastructure occur together within or in close proximity to a designated site. Likely significant impacts are as previously outlined. County (example) County and town development plans Potential in-combination impacts may arise where there is a requirement to provide for new infrastructure through implementation of county and town development plans. Provision of related transmission infrastructure may result in likely significant impacts as previously described. Projects Offshore energy generation projects In-combination impacts may arise at the interface between offshore and on shore infrastructure. Impacts that may occur include: — Habitat loss and disturbance. All terrestrial based designated sites may be affected, depending on where infrastructure and transmission lines are located/routed. Loss of habitats may also occur in the littoral and coastal zones. Habitat loss will be grater where underground cables are installed. — Sediment pollution and associated hydrological impacts where surface water dependant species and habitats are affected. Salmon, lamprey, white clawed crayfish and freshwater pearl mussel may potentially be affected. — Contamination of surface and groundwater with pollutants (e.g. fuels, lubricants, concrete) during construction. Salmon, lamprey, white clawed crayfish and freshwater pearl mussel may potentially be affected. — Disturbance of species during construction and maintenance activities. Species that may be affected include nesting and overwintering birds in coastal and freshwater SPAs; marine mammals, where interconnection between offshore and onshore infrastructure occurs; otters and kingfishers, where development occurs adjacent to or crossing watercourses; bats, where development affects woodlands, hedgerows or roosting sites. The assessment concluded that development of a new energy generation infrastructure when combined with other economic developments will potentially lead to habitat and/or species loss, species/population fragmentation and changes in water quality/quality. These potential conflicts could be mitigated by measures outlined later in the appropriate assessment and they would be addressed by lower tier environmental assessment, as appropriate. Assessment of potential significant effects and proposal of mitigation measures As previously mentioned, the Grid25 Implementation Programme provides an indicative overview of the general approach proposed for the future development of the grid and does not prescribe exactly the location of infrastructure. As such, this has the effect of limiting the level of assessment that can be undertaken and means that the assessment of potential significant effects has to be made in general terms. A general examination of impacts and sensitivities was therefore carried out. The assessment identified the types of impacts on the habitats and species affected that could be envisaged for the following main components of the IP: — overhead transmission lines; — underground cables; — construction of new substations and extension of existing substations; — reinforcement of the transmission system in the regions. For the latter, the main sensitivities in each region were identified and recommendations to avoid the expected impacts were outlined (e.g. avoidance of certain particularly sensitive areas in the reinforcement of the transmission system in the region, encourage to locate sub-stations and overhead routes on urban land, or in areas that contain dense corridors of anciently established settlement while avoiding more sensitive upland interiors etc.). The assessment also identified the impacts for a number of network developments that have progressed to detailed design stage (although the location and route of these projects is not fixed yet) on the Natura 2000 sites located in their proximity and therefore having potential to be affected by the individual projects in question. Due to the strategic nature of the Grid25 IP, it could not be conclusively stated at that stage that the IP will not adversely affect the integrity of the Natura 2000 network. Therefore, mitigation measures were proposed to ensure that significant impacts are avoided. Two levels of mitigation measures have been proposed. The first level of measures will guide the strategic approach to mitigating impacts and the second level of mitigation measures are more impact specific and shall be applied where significant impacts are identified following project level environmental impact assessment (EIA) and appropriate assessment. General mitigation measures are outlined for the main categories of impact identified and for the main habitats and species potentially affected. For instance, regarding general habitat loss and disturbance, avoidance and mitigation measures are described for bogs and peatland areas, birds, bats, otters, water dependant habitats and species, freshwater pearl mussel, other protected species, etc. The consideration of mitigation measures will prioritise the avoidance of impacts in the first place and mitigate impacts where these cannot be avoided. In addition, all lower level projects arising through the implementation of the IP will themselves be subject to appropriate assessment when further details of design and location are known. Having incorporated mitigation measures, it is considered that the Grid25 Implementation Programme will not have a significant adverse effect on the integrity of the Natura 2000 network. Nevertheless, all the projects to be implemented in the framework of the IP will be screened and subject to appropriate assessment as required. Source: Natura Impact Statement in support of the Appropriate Assessment of the Grid25 implementation programme. Available at: https://www.eirgridgroup.com/site-files/library/EirGrid/Natura-Impact-Statement-in-Support-of-the-Appropriate-Assessment-of-the-Grid25-Implementation-Plan.pdf

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Source: EUR-Lex (Cellar) · retrieved 2026-09-07