When considering planning applications for data centre developments, the Planning Authority assesses not only the impacts arising from the proposed development itself but also the potential cumulative impacts arising from existing, permitted and reasonably foreseeable developments in accordance with the land use zoning in the wider area.

Depending on the nature and scale of the proposal, cumulative assessment may consider matters such as traffic generation, noise, air quality, visual impact, utility demand, backup power generation, greenhouse gas emissions and effects on environmental receptors. Data centre developments are also assessed against the relevant policies and objectives of the South Dublin County Development Plan 2022-2028, including Policy EDE7 "Space Extensive Land Uses".

Under the EIA Directives, the most recent of which is Directive 2014/52/EU, certain public and private projects that are likely to have significant effects on the environment are required to go through the environmental assessment process. The EIA Directives have been transposed into the Irish planning consent system by way of the Planning and Development Acts 2000 (as amended) and the Planning and Development Regulations 2001 (as amended).

Part 2 of Schedule 5 of the Planning and Development Regulations 2001, as amended, sets out the types of development for which mandatory EIA is required. In addition, there is provision for sub-threshold development to be subject to EIA where proposed development is of a type listed in Part 2 of Schedule 5 but does not equal or exceed the threshold and it has been determined that the proposed development is likely to have a significant effect on the environment. Depending on the scale and nature of the proposal, data centre developments may be subject to mandatory EIA, sub-threshold EIA screening or neither process, with each application assessed having regard to the requirements of planning and environmental legislation.

Environmental Impact Assessments examine potential impacts which address direct, indirect, secondary, cumulative, transboundary, short, medium and long term, permanent, temporary, positive and negative effects, as well as impact interactions. This includes consideration of a "Do Nothing" impact which describes the environment as it would be in the future if the development is not carried out.

Therefore, where developments, including data centres, meet the mandatory thresholds for assessment or are determined by way of set criteria to meet the sub-threshold standards, their cumulative impact is assessed and considered as part of the planning application.