4.3.3. SIGNIFICANCE ASSESSMENT
Determination of Receptor Sensitivity
In accordance with IEMA guidance receptors considered include:
- Human health receptors (e.g., construction workers and operational and maintenance staff); and
- Project Infrastructure (onshore and offshore).
Sensitivity, in relation to climate change vulnerability, for each receptor has been determined using quantifiable data as well as professional judgement. In accordance with IEMA guidance the following have been considered:
- Susceptibility – ability for the receptor to be affected by climate change;
- Vulnerability – potential exposure of receptor to climate change; and
- Value – importance of receptor.
Susceptibility and vulnerability have been determined based on the criteria set out in IEMA guidance and shown in Table 4-5 and Table 4-6. Criteria for defining a receptor’s value are set out in Table 4-7.
Table 4-5 – Criteria for Determining Susceptibility
Susceptibility | Criteria |
High (score: 4) | Receptor has no ability to withstand/not be substantially altered by the projected changes to the existing/prevailing climatic factors (e.g. lose much of its original function and form). |
Medium (score 3) | Receptor has some limited ability to withstand/not be altered by the projected changes to the existing/prevailing climatic conditions (e.g. retain elements of its original function and form). |
Low (score 2) | Receptor has the ability to withstand/not be altered much by the projected changes to the existing/prevailing climatic factors (e.g. retain much of its original function and form). |
Negligible (score 1) | Receptor can withstand/not be altered by the projected changes to the existing/prevailing climatic factors (e.g. it will retain all of its original function and form). |
Table 4-6 - Criteria for Determining Vulnerability
Vulnerability | Criteria |
High (score: 4) | High certainty that receptor will be directly exposed to climate changes |
Medium (score 3) | Medium certainty that receptor will be exposed to climate changes
|
Low (score 2) | Low certainty that receptor will be exposed to climate changes
|
Negligible (score 1) | Uncertain if receptor will be exposed to climate changes
|
Table 4-7 - Criteria for Determining Value
Value | Criteria |
High (score: 4) | High importance, for example internationally important or high economic value |
Medium (score 3) | Medium importance, for example nationally important or medium economic value |
Low (score 2) | Low importance, for example locally important or low economic value |
Negligible (score 1) | Negligible importance, for example not important or of negligible economic value. |
The receptor’s sensitivity is a combination of its vulnerability, susceptibility and value score. It is determined by summing these scores and then categorising as follows:
- Score 0-4 Negligible
- Score 5-7 Low
- Score 8-9 Medium
- Score 10-12 High
Determination of Impact Magnitude
Due to the inherent uncertainty of future climate change predictions, a risk-based approach has been used to identify impact magnitude, after mitigation, which considers a combination of the consequence of a climate change impact occurring and the probability of occurrence.
The probability of a specific climate variable changing is determined using available data and professional judgement. The categories range from negligible through low and medium to high. When defining probability, consideration has been given to the projected return periods of future events (where known), and the confidence in the direction of projected changes.
The consequence of climate change impacts has been defined as shown in Table 4-8.
Table 4-8 – Criteria for Determining Impact Consequence
Consequence | Criteria |
|---|---|
High | Consequences have very large economic cost or affect assets that are integral to critically important systems. Consequences cause very large safety risks (long term injury/illness or risk of fatality) or very poor performance (e.g., outage or quality problems lasting >48 hours). Consequences cause prolonged negative national reporting. Consequences cause very large environmental pollution or harm resulting in a major breach in compliance and prosecution or adversely affect internationally important species or habitat. Consequences occur many times during the life of the Project, e.g., could occur seasonally or last for many months/years. |
Medium | Consequences have a large economic cost or affect important systems, Consequences cause large safety risks (short term injury or illness) or poor performance (e.g., moderate outage or quality problems lasting <48 hours) Consequences cause negative regional media or social media. Consequences cause large environmental pollution or harm resulting in a regulatory non-compliance or affect nationally important species or habitat Consequences occur more than once or lasting several months. |
Low | Consequences cause safety risks (minor harm or near miss) or slightly reduce performance (e.g., outage or quality problems lasting <1 hour). Consequences cause negative local media or adverse local stakeholder reaction Consequences cause moderate environmental pollution or harm that may cause non-compliance of regional or local policy or affecting locally important species or habitat Consequences occur once or last several weeks |
Negligible | Consequences have little economic cost or affect individual assets and can be easily repaired or replaced Consequences cause very small or no safety risks or reduced performance Consequences have little or no public interest Consequences have no statutory controls or cause negligible environmental pollution or harm to receptors of little or no importance Consequences unlikely to occur during projects design life or lasts for only a few days |
The impact magnitude is determined by considering the impact’s consequence and probability in combination as shown in Table 4-9.
Table 4-9 – Determining Impact Magnitude
| Probability | ||||||
High | Medium | Low | Negligible | ||||
High | High | High | Medium | Low | |||
Medium | High | Medium | Low | Negligible | |||
Low | Medium | Low | Negligible | Negligible | |||
Negligible | Low | Negligible | Negligible | Negligible | |||
Determination of Significance
The significance of effect is determined by considering the relationship between the sensitivity of the receptor and the impact magnitude. Major or Major/Moderate effects are deemed to be significant. Everything less than this (Moderate, Moderate/Minor, Minor, Minor/Negligible and Negligible) are deemed to be not significant. Table 4-10 acts as a guide and professional judgement is used at each step to make a reasoned judgement on whether an effect is significant or not.
Table 4-10 – Determining Significance of Effect
| Impact magnitude | ||||
High | Medium | Low | Negligible | ||
High | Major | Major / Moderate | Moderate / Minor | Minor / Negligible | |
Medium | Major / Moderate | Moderate | Minor | Negligible | |
Low | Moderate / Minor | Minor | Minor | Negligible | |
Negligible | Minor / Negligible | Negligible | Negligible | Negligible | |
4.4. ASSESSMENT
4.4.1. RECEPTORS
Table 4-11 shows the receptors that have been considered in the climate vulnerability assessment and shows how their sensitivity has been derived.
Table 4-11 - Receptors Considered in the Impact Assessment
Receptor | Susceptibility | Vulnerability | Value | Sensitivity |
|---|---|---|---|---|
Energy production | Wind turbines can operate at a range of wind speeds but are not able to operate in extremely high or low wind. They therefore have some resilience to withstand the projected changes Low (2) | There is uncertainty in future wind projections. Receptor may therefore not be exposed to adverse changes Low (1) | Receptor is of medium importance (energy production at extremes of prevailing climatic conditions) Medium (3) | Low (6) |
Assets | With embedded mitigation receptor has the ability to withstand/not be altered much by the projected changes to the existing/prevailing climatic factors Low (2) | Assets are likely to be exposed to projected climatic changes. Medium (3) | Receptor is of medium importance (assets can be maintained and replaced) Medium (3) | Medium (8) |
Staff wellbeing and health and safety | Humans are resilient to projected climatic changes Low (2) | Receptor is likely to be exposed to projected climatic changes. Medium (3) | Receptor is of high importance High (4) | Medium (9) |
4.4.2. POTENTIAL CONSTRUCTION IMPACTS
The Project's construction is not expected to be so far in the future that the current climate conditions will notably change. Gradual changes to average climatic conditions are therefore not expected to impact construction.
If construction coincides with extreme weather event(s), such as drought or storms, which are projected to become more frequent and more severe, there may be construction related impacts. These are set out in the following subsections.
Delayed Construction Schedule
Extreme weather events that compromise the viability of the construction site, for example, heavy rain resulting in closure of local roads and power cuts due to flooding or flood inundation of the construction site itself, could restrict working hours and delay construction.
Delays could also be linked to unsuitable weather conditions for certain construction activities or damage to construction materials, plant and equipment.
During installation, specialist vessels are required for heavy lifting and piling operations; these vessels are often jack-up vessels that are fitted with long support legs that can be raised or lowered. These vessels are particularly sensitive to wind speed, wave height and wave period when en route from port to the offshore location, transitioning between wind turbines, and heavy lifting crane operations at height.
Increased Health and Safety Risks
During severe weather events, for example, extreme heat events, there could be increased health and safety risks to the workforce.
Mitigation and Assessment
Construction impacts are addressed as required by the relevant topics within the Onshore and Offshore EIA Reports. Potential construction related surface water flood risks related to extreme weather are addressed within the Geology, Hydrology, Soils and Flood Risk Chapter (Onshore EIA Report, Volume 1, Chapter 11). Any potential construction impacts related to climate that are not covered by other chapters in the EIA Reports will be managed through the CEMP for example by the inclusion of severe weather construction plans and risk assessments.
4.4.3. POTENTIAL OPERATION AND MAINTENANCE IMPACTS
The operation and maintenance phase impact assessment for Climate Vulnerability is set out in Table 4-12.
Table 4-12 – Operation and Maintenance Phase Impact Assessment
Baseline | Impact Assessment | |||||
|---|---|---|---|---|---|---|
Receptor | Receptor Sensitivity | Impact | Mitigation | Impact Magnitude | Residual Effect | Significance |
Energy production | ||||||
Energy production
| Low | Climate change induced changes in wind patterns and extremes could fundamentally affect wind power schemes. The energy density of wind is determined by the global energy balance and the atmospheric motion that results from it. The main mechanisms by which global climate change impacts wind energy endowments are shifts in the geographical distribution and the variability of wind speed. These could both affect the economic feasibility of exploiting wind resources but also the reliability of electricity production (Solaun & Cerda, 2019). Too little wind and the turbines cannot operate and, whilst power generated by wind speeds increases with increasing wind speed, too much wind and a cut-out speed can be reached, triggering a shut down to prevent unnecessary strain on the rotors. | Adaptation to storms and high winds include preventative steps in both the design and operation and maintenance phases of the Project. Examples include high wind ride through, wind turbine load control and grid loss survival modes/island modes. Further, modern offshore wind turbines are being designed through these adaptive systems to withstand typhoon/hurricane events as they move into offshore locations more prone to these climatic conditions. | Probability – Low Consequence – Medium Magnitude – Low | There has been very little variability in wind trends across Europe. What is seen in the data is that variability tends to exceed seasonal and interannual and decadal tendencies (Bett et al., 2017). Projecting future wind patterns is complex and there is therefore uncertainty with regard to exactly how climate change could affect wind. However, changes to extremes are expected with more severe and regular storms likely to generate high winds more regularly. After including the adaptation measures noted under ‘mitigation’ the effect on energy production over the life span of the project is expected to be minor.
| Minor Not significant |
Assets | ||||||
Exposed materials on assets | Medium | Extreme weather could damage exposed infrastructure requiring increased maintenance and shorter replacement cycles. For example, extreme heat could cause:
| The design utilises underground cables to ensure impacts from high winds on transmission infrastructure are avoided. The Project’s flood risk assessment mitigates impacts related to flood risk and sea level rise on assets by incorporating climate change considerations during site selection (Appendix 11.1 of the onshore EIA)). Appropriate land drainage design will be conducted and pre- and post- drainage requirements implemented as appropriate. | Probability – Medium Consequence – Low Magnitude – Low |
| Minor Not significant |
Onshore assets | Medium | In the future climate change may increase risks associated with coastal and fluvial flooding which could damage onshore assets by scour or inundation. This includes foundations and buried infrastructure particularly where it is close to or crosses streams or burns. | The flood risk assessment is presented in Appendix 11.1 of the onshore EIA. It includes consideration of climate change. The Project design has already taken into account potential options for scour protection and subsidence mitigation. Details will be confirmed at the final design stage, once all specific locations have been confirmed. The options would include concrete mattresses, rock layering and artificial fronds. Separate flood modelling has been carried out. The coastal flood level under a high-emissions scenario (RCP8.5) in 2075 has been determined. The work has been undertaken as part of the site selection process in order to ensure the consideration of climate change.[15] | Probability – Medium Consequence – Low Magnitude – Low | The Project does not increase flood risk elsewhere (i.e., no land raising in the functional flood plain and no displacement of flood storage or diversion of overland flood flow pathways to other sensitive receptors).
| Minor Not significant |
Onshore assets | Medium | The stability of onshore structures could be affected as:
| Risk will be managed by best practice design and construction. To avoid waterlogging around key structures drainage (both permanent and temporary) will be included. Geotechnical construction risks will be controlled where appropriate, for example by:
| Probability – Medium Consequence – Low Magnitude – Low | With embedded mitigation in place the risk of significant impacts is controlled. | Minor Not significant |
Staff wellbeing and health and safety | ||||||
Staff wellbeing and occupational health and safety | Medium | Exposure of employees and contractors to higher summer temperatures and heatwave conditions may adversely affect staff working conditions and schedules. Additionally, more regular and severe extreme weather brought about by climate change may increase the risk of a weather related accidents. With regard to climate hazards hotter temperatures and lightening are considered to be the main potential weather related risks. Climate change could also affect health and safety by affecting metocean conditions. Operation & Maintenance of offshore wind turbines requires scheduled and sometimes unscheduled activities which requires the transfer of personnel and equipment where safe access and suitable vessels are required. Safe access is sensitive to wind speeds, significant wave height and wave period including port access, navigating between the port and the offshore site and the transition from the vessel to the turbine or offshore substation. Studies have also shown the impacts of seasickness on crew members and their ability to affectively operate. Whilst on the wind turbine itself Operation & Maintenance can be affected by wind speeds due to working at height. | Changes in climate may necessitate new ways of working or additional PPE. Provision of weather forecasts and metocean data to understand weather windows for access. | Probability – Medium Consequence – Low Magnitude – Low | With appropriate mitigation, such as occupational health and safety management and marine coordination plans, risks can be managed to avoid or mitigate to acceptable levels any potential impacts on staff well being or occupational health and safety. | Minor Not significant |