16.8. Methodology for Assessment of Effects

The major accidents and disasters assessment of effects has followed the methodology set out in the following guidance:

This methodology directed the assessment to focus on low likelihood but potentially high consequence events such as major spill, explosion, fire, etc. Minor incidents, including spills and sediment loss, are addressed in the Array EIA Report in the relevant topic chapters and this chapter therefore focuses on major events only.
The methodology followed three steps: screening, scoping and assessment. The screening stage aimed to identify whether a development is vulnerable to major accidents and/or disasters and to consider whether a development could lead to a significant effect. The scoping stage determined in more detail whether there is potential for significant effects to arise as a result of a major accident and/or disaster associated with a development. The assessment stage provided further understanding of the likelihood of a risk event occurring and identified the requirement for further mitigation.
In addition, the major accidents and/or disasters assessment of effects has considered the legislative framework as defined by the HSWA 1974 and its relevant statutory provisions, although it should be noted that under UK’s health and safety legislation, Health and Safety Executive (HSE) does not have a role in examining risk or hazard assessments unless the circumstances are covered by specific regulations.

16.9. Measures Adopted as Part of the Array

As part of the Array design process, a number of designed in measures have been proposed to reduce the potential for impacts within the following chapters (outlined in Table 16.4 Open ▸ ):

As there is a commitment to implementing these measures described within each chapter listed above, they are considered inherently part of the design of the Array and have therefore been considered in the assessment presented in 16.10. These measures are considered standard industry practice for this type of development.

Following the guidance outlined within the IEMA (2020) and given the location of the Array, the Array has a vulnerability to major accidents and/or disasters and therefore has been screened into assessment included in this Array EIA Report. Hazards have been scoped out if it is concluded that there is no potential vulnerability to and of the Array to cause or be impacted by major accidents and/or disasters. If the hazard is scoped out it is not considered further in this chapter ( Table 16.5 Open ▸ ).
Although there are a significant number of designed in measures in place, a full assessment of the vulnerability of the Array to risks of major accidents and disasters have been undertaken with consideration given to the potential for the Array to result in a major accident or disaster.

the Array is not vulnerable to the hazard, or will not cause the hazard;
the hazard is unlikely to result in effects that cause a fatality, multiple fatalities, permanent injury, widespread of irreversible harm or damage i.e. would not result in a major accident and/or disaster;
there is either no credible pathway or receptor in terms of EIA Regulations; and
the accident involves a workplace hazard, which can only impact the workers undertaking the task such as falls from height or misuse of tools. This is considered to be an occupational health and safety incident which is managed through compliance with the Management of Health and Safety Work Regulations and not the intended purpose of EIA (see paragraph 89).

Under IEMA (2020) guidance, other sources of information were used to identify potential hazards on a regional and national scale. These documents were as follows:

National Risk Register (HM Government, 2023); and
Community Risk Register (North Scotland) (Regional Resilience Partnership (RRP), 2022).

In line with the IEMA guidance (IEMA, 2020), standalone risk assessments for major accidents and disasters have not been undertaken as existing public sources of data are available to inform the baseline. The sources used are detailed in each of the chapters summarised below. As detailed in paragraph 87, work hazards are exempt from the scope of this assessment as these hazards are managed through relevant HSE legislation.
Table 16.5 Open ▸ outlines the scoping of the vulnerability of the Array to the baseline anthropogenic sources of hazards which have potential for significant adverse effects.
In addition to the existing baseline procedures, the Array will introduce additional pressures that may give rise to the potential for accidents to impact on the receiving environment, these are listed in Table 16.6 Open ▸ . As before, each pressure is assessed individually and scoped in/out of further assessment and a justification for scoping is provided.
The Array includes designed in measures adopted as part of the Array that will reduce the potential for any accidents during construction, operation and maintenance and decommissioning. These are outlined in Table 16.6 Open ▸ .

In addition to the existing baseline procedures, the Array will introduce additional pressures that may give rise to the potential for accidents to impact on the receiving environment, these are listed in Table 16.6 Open ▸ . As before, each pressure is assessed individually and scoped in/out of further assessment and a justification for scoping is provided.
The Array includes designed in measures adopted as part of the Array that will reduce the potential for any accidents during construction, operation and maintenance and decommissioning. These are outlined in Table 16.6 Open ▸ .

Following the guidance outlined within IEMA (2020) all scoped in risk events have been assessed, both in terms of the Array potential vulnerability to existing major accident and/or disasters and in terms of its potential to cause accidents/disasters. Multidiscipline impacts, designed in measures and the potential requirement of additional mitigation measures are considered in assessing whether each potential risk event is being managed to an acceptable level.
Table 16.7 Open ▸ details the assessment of vulnerability of and potential for the Array to be impacted or cause major accidents and/or disasters.