Annex 1: Eskdalemuir working group and policy proposals
1. The Eskdalemuir Seismic Array (EKA) is a seismological monitoring station in the Scottish Borders which forms part of the UK's obligations under the Comprehensive Test Ban Treaty (CTBT). The array's operation can be compromised by excessive seismic noise in the vicinity, which is proven to be produced by wind turbines operating within a 50 km consultation zone around the array.
2. In response to wind turbine development on land near to the EKA, a study was conducted to examine the impacts of wind turbine vibration on the array. The study's findings showed that wind turbines could have an impact on the EKA and resulted in the introduction of a 10km radius 'exclusion zone' and a 50km radius statutory consultation zone for all onshore wind development. The 50km consultation zone covers an area of almost 8000 km2, covering the South of Scotland and the North of England. This represents approximately 10% of Scotland's land mass and around 3% of the UK's total land area.
3. The 2005 Styles Report recommended a limit of 0.336 nm of seismic disturbance to prevent the array's operation being comprised, and this was adopted for any development within the consultation zone. This was followed by the 2014 work undertaken by Xi Engineering, on behalf of the Eskdalemuir Working Group (see para 9), which developed a spreadsheet tool enabling the MoD to monitor this budget.
4. Currently, the 0.336nm budget has been allocated between operational wind farms and developments still within the planning and consenting system. Based on current methodology, there can be no further budget allocated until this theoretical budget is returned, either through decommissioning or determination of sites. The MoD have a record of all onshore wind farms proposed or built in the 50km zone, which includes any applications that do have budget allocated.
5. The MoD is provided with details of specific turbines and their locations at development consent application stage. These details are entered into the budget tool spreadsheet, which then calculates the predicted 'noise' from that proposed development. If the proposal would not exceed the remaining available budget, the MoD offers no objection and the development is added to the budget tool.
6. At the moment, the noise budget for the zone has been breached, meaning the MoD will object to any and all developments within the consultation zone in order to protect the operations of the array.
7. Currently, there is in excess of 1.7GW of planned onshore wind developments that are being impacted on by the current policy environment within the Eskdalemuir area. The Climate Change Committee (CCC) have estimated that the UK will need 22-29 GW on onshore wind by 2050 to meet our decarbonisation targets, and 1.7GW represents around one quarter of Scottish pipeline projects.
8. Unlocking potential capacity will require decisive and meaningful action from both Scottish Government, UK Government and MoD. To do so, we must recognise that:
- Safeguarding of the array lies within the MoD policy remit.
- Maximisation of renewable energy deployment lies within the Scottish Government policy remit.
9. The Eskdalemuir Working Group (EWG) was reformed in 2018 to find an enduring solution to unlock renewable potential in the area through collaboratively working with MoD, industry groups and developers. Since its reformation in 2018 the group has continued to grow in membership and Scottish Government consider that a restructure may be needed to retain its efficiency.
10. A "Policy Route" was explored by the group over the course of 2018-2019 but no full resolution could be found. As a result the Scottish Government opted to consider a technical approach to the issue over the course of 2020/21.
11. Scottish Government commissioned Xi Engineering to undertake a technical analysis of the budget calculation tool currently used by MoD. The purpose of this was to investigate potential headroom within the assumed seismic contribution of existing sites within the area. Three phases of work have been conducted by Xi Engineering which specifically look at the existing budget allocation algorithm used by MoD. The results of which have all been made publically available on the Scottish Renewables website. These combined phases of work showed that there is a gross overestimation of the safety factor required when accounting for the seismic contributions of individual turbines.
12. A final phase of work, comprising of a measurement campaign at an additional seven sites, has been funded by Scottish Government, BEIS, AIFCL and members of the renewables industry and its final report is due later this year.
13. The Scottish Government is committed to the most efficient use of our renewable generating potential and recognise that EKA is acting as a barrier to deployment at present. We are therefore seeking views on potential Energy Policy options. These will be informed by both the existing studies conducted by Xi Engineering and the upcoming results of Phase 4. It is important to note that no policy decisions can be take ahead of further evidence.
14. As we see it, there are four potential policy options which could be adopted:
- Option 1: There shall be no onshore wind developments constructed within Scotland which lie within 15km of the Eskdalemuir Seismic Array. (Noting that without the final report from Phase 4 measurements, we cannot confirm that 15km is the most appropriate distance to set this at).
- Option 2: Any onshore wind development within Scotland which lies between 10km and 20km of the Eskdalemuir Seismic Array will be required to demonstrate, to the satisfaction of the Ministry of Defence, that they can sufficiently mitigate the impact their development would have of the array to an acceptable level.
- Option 3: Combination of the two options above. A hard, no build area and an additional buffer zone where mitigation is required.
- Option 4: Make no changes. The no build limit remains at 10km and no additional measures are put in place.
15. Any issues around budget allocation and the methodology for calculating impact upon the budget lie solely within the remit of the Ministry of Defence. The Scottish Government is keen to continue to work with the MoD, and support them as they develop a policy to govern these aspects.
Annex 1: Eskdalemuir working group and policy proposals – consultation questions
26. Does the above accurately reflect the current position in relation to the Eskdalemuir Seismic Array and the barrier it presents to deployment in Scotland?
27. Acknowledging that the Scottish Government require further evidence before taking a policy decision, at this point and reflecting the options outlined above do you/your organisation have any thoughts?
28. If Option 2 or Option 3 were to be selected, how could we best achieve or calculate an acceptable level of impact?
(One example being an agreement of a standard noise budget to MW generated proportional allocation I.e., for X MW generated = X amount of budget allocated).
29. Do you/your organisation have any thoughts on how the EWG might be restructured to ensure continued engagement for interested parties whilst maintaining the core purpose of the group?
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