17.8. Key Parameters for Assessment

17.8.1. Maximum Design Scenario

  1. The maximum design scenarios identified in Table 17.7   Open ▸ are those expected to have the potential to result in the greatest impact on an identified receptor or receptor group. These scenarios have been selected from the details provided in volume 1, chapter 3 of the Array EIA Report. Effects of greater adverse significance are not predicted to arise should any other development scenario within the Project Description (volume 1, chapter 3) and assessed here, be taken forward in the final design.
Table 17.7:
Maximum Design Scenario Considered for Each Potential Impact as Part of the Assessment of LSE1 on and from Climate Change

Table 17.7: Maximum Design Scenario Considered for Each Potential Impact as Part of the Assessment of LSE1 on and from Climate Change

17.8.2. Impacts Scoped Out of the Assessment

  1. On the basis of the baseline environment and the Project Description outlined in volume 1, chapter 3 of the Array EIA Report, one impact is proposed to be scoped out of the assessment for climatic effects.
  2. This impact is outlined, together with a justification for scoping it out, in Table 17.8   Open ▸ .

 

Table 17.8:
Impact Scoped Out of the Assessment for Climatic Effects (Tick Confirms the Impact is Scoped Out)

Table 17.8: Impact Scoped Out of the Assessment for Climatic Effects (Tick Confirms the Impact is Scoped Out)

 

17.9. Methodology for Assessment of Effects

17.9.1. Overview

  1. The climate change assessment of effects has followed the methodology set out in volume 1, chapter 6 of the Array EIA Report. Specific to the climatic effects EIA, the following guidance documents have also been considered:
  • IEMA guidance on Climate Change Adaption and Resilience (IEMA, 2020); and
  • IEMA guidance on ‘Assessing Greenhouse Gas Emissions and Evaluating their Significance’ (IEMA, 2022).
  1. In addition to the overarching policy and legislation as described in volume 1, chapter 2 of this Array EIA Report, national climate change policy and legislation relevant to the climatic effects impact assessment is set out in section 17.4. In order to undertake a climatic effects impact assessment, information gathered in the GHG assessment technical report (volume 3, appendix 17.1) and the CCRA technical report (volume 3, appendix 17.2) have been utilised. This information is sourced from primary calculations and secondary sources to calculate the effect of the Array on and from climate change.

                        GHG Emissions Assessment Methodology

  1. GHG emissions have been estimated by applying published emissions factors to activities in the baseline and to those required for the Array. The emissions factors relate to a given level of activity, or amount of fuel, energy or materials used to the mass of GHGs released as a consequence. The GHGs considered in this assessment are those in the ‘Kyoto basket’ of global warming gases[4] expressed as their CO2-equivalent (CO2e) global warming potential (GWP). This is denoted by CO2e units in emissions factors and calculation results. GWPs used are typically the 100-year factors in the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (IPCC, 2013) or as otherwise defined for national reporting under the UNFCCC.
  2. Additional guidance used for the quantification of GHG emissions includes:
  • DESNZ (2023a) Valuation of Energy Use and Greenhouse Gas: Supplementary guidance to the HM Treasury Green Book;
  • UK Government GHG Conversion Factors for Company Reporting (DESNZ and Defra, 2023); and
  • the Greenhouse Gas Protocol suite of documents WRI and World Business Council for Sustainable Development (WBCSD) (2004).
  1. GHG emissions caused by an activity are often categorised into ‘scope 1’, ‘scope 2’ or ‘scope 3’ emissions, following the guidance of the WRI and the WBCSD Greenhouse Gas Protocol suite of guidance documents (WRI and WBSCD, 2004).
  • Scope 1 emissions: direct GHG emissions from sources owned or controlled by the company, e.g. from combustion of fuel at an installation.
  • Scope 2 emissions: caused indirectly by consumption of purchased energy, e.g. from generating electricity supplied through the national grid to an installation.
  • Scope 3 emissions: all other indirect emissions occurring as a consequence of the activities of the company, e.g. in the upstream extraction, processing and transport of materials consumed or the use of sold products or services. Downstream use of products and services sold to customers would also be captured under Scope 3 emissions.
  1. This assessment has sought to include emissions from all three scopes, where this is material and reasonably practicable from the information and emissions factors available, to capture the impacts attributable most completely to the Array. These emissions shall not be separated out by defined scopes (scopes 1, 2 or 3) in the assessment.
  2. The assessment has considered:
  • the GHG emissions arising from the Array (during construction, operation and maintenance, and decommissioning phases);
  • any GHG emissions that it are avoided, compared to the current or future baseline; and
  • the net impact on climate change due to these changes in GHG emissions overall.
  1. As previously discussed in paragraph 42, construction phase GHG emissions associated with the manufacturing of components may occur outside the territorial boundary of the UK and hence outside the scope of the UK’s national carbon budget. However, in recognition of the climate change effect of GHG emissions (wherever occurring) and  to avoid ‘carbon leakage’ overseas when reducing UK emissions, the full life cycle GHG emissions of the Array, including emissions associated with the construction phase (wherever they derive, globally, where it is reasonably practicable to make assumptions for those emissions), have been evaluated where possible when determining the significance of effects.
  2. The GHG technical report (volume 3, appendix 17.1), which provides further details of the GHG emissions assessment methodology, should be read alongside this chapter.

                        CCRA Methodology

  1. Baseline offshore climatic conditions have been sourced from observational data collated within the UK Offshore Energy Strategic Environmental Assessment (BEIS, 2022c), IPCC Sixth Assessment Reporting of the physical science (IPCC, 2021) and the physical processes technical report (volume 3, appendix 7.1). Information from the UKCP18 RCP8.5 has been drawn upon in addition to the UK CCRA3 to establish UK marine climate projections for the 21st century through to 2100.
  2. The CCRA technical report (volume 3, appendix 17.2) should be read alongside this chapter, which provides further detail of the approach and data input.
  3. A high level screening risk assessment has been undertaken, considering the hazard, potential severity of impact on the Array and workers, probability of that impact, and level of influence the Array design can have on the risk.
  4. Where potentially significant impacts have been identified at the screening stage prior to any mitigation, further assessment has been undertaken with consideration of appropriate mitigation to determine whether significant residual risks are likely.

17.9.2. Criteria for Assessment of Effects

  1. When determining the significance of effects, a two stage process is used which involves defining the magnitude of the potential impacts and the sensitivity of the receptors. This section describes the criteria applied in this chapter to assign values to the magnitude of potential impacts and the sensitivity of the receptors. The criteria for determining the significance of effects have been divided into two categories:
  • assessment of the significance of the effect of the Array on climate change (GHG assessment); and
  • assessment of the significance of the effect from climatic changes on the Array (CCRA).
  1. The impact assessment criteria for each of these categories is set out below.

                        Impact Assessment Criteria: GHG Emissions

                        Magnitude of impact
  1. In accordance with the IEMA Guidance (2022) where GHG emissions can be quantified directly and expressed based on their GWP as tonnes of CO2e emitted, the magnitude of impact is reported numerically. Where a quantifiable figure is not possible, for example due to a lack of available data at early design stage, this is expressed qualitatively, based on professional judgement.
                        Sensitivity of receptor
  1. GHG emissions have a global effect rather than directly affecting any specific local receptor to which a level of sensitivity can be assigned. The global atmospheric mass of the relevant GHGs and consequent warming potential, expressed in CO2e, has therefore been treated as a single receptor of high sensitivity (given the importance of the global climate as a receptor).
                        Significance of effect
  1. Assessment guidance for GHG emissions (IEMA, 2022) describes five levels of significance for emissions resulting from a development, each based on whether the GHG emission impact of the development will support or undermine a science-based 1.5°C compatible trajectory towards net zero, in line with the goals of the Paris Agreement (UN, 2015). To aid in considering whether climatic effects are significant, IEMA (2022) recommends that GHG emissions should be contextualised against pre-determined carbon budgets, or applicable existing and emerging policy and performance standards where a budget is not available. It is a matter of professional judgement to integrate these sources of evidence and evaluate them in the context of significance.
  2. Taking the guidance into account, the following have been considered in contextualising the Array GHG emissions:
  • the magnitude of net GHG emissions as a percentage of UK national carbon budgets (where feasible and where carbon budgets are available); and
  • whether the Array contributes to, and is in line with, the UK’s policy for GHG emissions reductions, where these are consistent with science-based commitments to limit global climate change to an internationally agreed level (as determined by the UK’s nationally determined contribution (NDC) to the Paris Agreement (BEIS, 2022a)).
  1. Effects from GHG emissions are described in this chapter as adverse (major, moderate or minor), negligible or beneficial based on the following definitions, which closely follow the examples in Box 3 of the IEMA guidance (IEMA, 2022) as detailed in Table 17.9   Open ▸ .

 

Table 17.9:
Guidance Definitions of Significance in Relation to GHG Emissions (IEMA, 2022)

Table 17.9: Guidance Definitions of Significance in Relation to GHG Emissions (IEMA, 2022)

 

  1. Major and moderate adverse and beneficial effects are considered to be significant in EIA terms. Minor adverse and negligible effects are not considered to be significant in EIA terms.
  2. GHG emissions associated with a proposed project are often reported as a whole life figure (net emissions) that takes account of all the Array’s phases. The net whole life figure is the key element for determining the Array’s whole life impact on climate change. However, it is noted in the IEMA guidance (2022) that due to the nature of GHG emissions, it is good practice to include a section that reports on the whole life GHG emissions associated with the Array, alongside the sections that assess construction, operation and maintenance and decommissioning effects in isolation.

                        Impact Assessment Criteria: CCRA

  1. IEMA guidance (IEMA, 2020) defines climate change resilience as the “ability to respond to changes in climate. If a receptor or project has good climate change resilience, it is able to respond to the changes in climate in a way that ensures it retains much of its original function and form. A receptor or project that has poor climate change resilience will lose much of its original function or form as the climate changes”.
  2. The methodology to assess impacts presented in the CCRA differs from many other EIA topics in that it considers how the resilience of a development is affected by an external factor (climate change) and not specifically how potential environmental receptors are affected by a development’s impacts. Consequentially, the CCRA cannot be assigned significance with respect to the severity of impacts in the same way as for the other topics. Instead, a risk-analysis based approach has been used for the assessment.
  3. As is detailed in the CCRA technical report (volume 3, appendix 17.2), a risk assessment has been undertaken, considering the hazard, potential severity of impact on the Array and its users (including their sensitivity and vulnerability), probability of that impact, and level of influence the Array design can have on the risk. Each of these factors is assigned a score of between 1 and 3, as shown in Table 17.10   Open ▸ below. These individual scores are summed to give a final total score. A total score of five or more (the minimum score where more than one element of the risk assessment score is above ‘one’) has been defined as a risk that could lead to a significant adverse or beneficial effect in EIA terms. By considering designed in measures adopted as part of the Array, professional judgement is used in determining whether impacts are likely to result in significant adverse or beneficial, or non-significant negligible effects in EIA terms.
  4. The criteria for defining the potential severity of a climate impact on the Array, probability of that impact, and influence factor of the design, used in this chapter to determine the significance of identified climate risks are outlined in Table 17.10   Open ▸ below.
Table 17.10:
Severity, Probability, and Influence Factor Definitions


Table 17.10: Severity, Probability, and Influence Factor Definitions