Sectoral marine plan for offshore wind energy: social and economic impact assessment scoping report
Sets out the methodology and scenarios for scoping and undertaking a socio-economic impact assessment.
A.11. Power Interconnectors
A.11.1 Sector Definition
This sector is concerned with the transmission of power through submarine cables, including international, national and inter-island links. This assessment excludes power cables to/from individual developments ( e.g. power supplies to oil and gas installations, export cables from offshore wind farms).
A.11.2 Overview of Activity
Electrical interconnection with other nations contributes to the UKs energy security, affordability and decarbonisation objectives. The UK currently has 3.5 GW of interconnection with other nations, 2 GW with France, 1 GW with the Netherlands and 500 MW with the Republic of Ireland ( Ofgem, 2017).
Figure A.11.1 shows the subsea power interconnectors present in Scottish waters. Information sources that can be used in the assessment are listed in Table A.11.1.
There is no agreed methodology for calculating the economic value of subsea power cables. In the absence of information on economic value, the capacity of interconnector cables may be used as an indicator of both value and activity ( UKMMAS, 2010).
With respect to future trends in sector activity, the power cable industry is experiencing significant growth, with several new projects currently in the installation and planning phases. While investment in these activities will be affected by the recent downturn in the economy in the short term, long-term drivers for competitive electricity markets and international energy cooperation are likely to maintain the impetus towards increasing the level of interconnector capacity ( AECOM and ABPmer, 2015).
Figure A.11.1 Power interconnectors in Scotland
Table A.11.1 Information sources for the power interconnectors sector
| Data Available | Information Source |
|---|---|
| Power interconnectors and transmission lines ( UK) | KIS-ORCA |
| UK Transmission network, including interconnectors | Ofgem website https://www.ofgem.gov.uk/electricity/transmission-networks/electricity-interconnectors Ofgem reports 2017; 2016 |
A.11.3 Potential Interactions with Offshore Wind
Table A.11.2 shows potential interaction pathways between power interconnectors and offshore wind arrays and export cables. Based on the approach to scoping described in Section 2 in the main report, the table also records whether the interaction:
- Is not likely to result in a significant socio-economic impact on the sector; or
- Is likely to result in a significant socio-economic impact on the sector and hence will require a detailed assessment;
The rationale underlying this expert judgement is provided in the table. Where it is not currently possible to make a judgement regarding the likelihood of a significant socio-economic impact due to insufficient information (for example, in relation to the extent of overlap between a sector activity and the DPO Areas) the table indicates that scoping will be required to be undertaken once sufficient information becomes available. Furthermore, as described in the main report, there is currently no information regarding the likely location of export cable routes/corridors and as such, it is not possible to undertake a meaningful assessment of the potential for any sector activity/export cable interaction to give rise to significant socio-economic effects. Rather, the potential for any interaction will be identified in Regional Locational Guidance.
Table A.11.2 Potential interaction pathways
| Potential Interaction |
Technology Aspect |
Potential Socio-economic Consequences |
Initial Scoping Assessment |
|---|---|---|---|
| Competition for space with potential future interconnectors ( DPO areas intersect proposed interconnector routes) |
Arrays (operation) |
Increased costs associated with new cable laying operations and cable crossings |
Any potential significant impacts would only be expected to occur where DPO areas overlap/intersect with future planned or proposed power interconnector routes that are likely to be constructed after agreements to lease have been issued in relation to DPO areas. The location of DPO areas is not currently available. However, it is considered likely that where there are current planned or proposed interconnectors routes are known, avoidance of this interaction should be possible through marine spatial planning. Scoping assessment to be completed once DPOs defined. |
| Export cables (operation) |
Increased costs associated with new cable laying operations |
Any potential significant impacts would only be expected to occur where export cables intersect with future planned or proposed power interconnector routes that are likely to be constructed after licence applications for array export cable routes have been submitted. Export cable routes are uncertain. Constraints inshore of DPOs will be identified in the RLG. No detailed assessment possible. |
|
| Cable crossings with existing interconnectors |
Export cables (construction) |
Additional costs to construct cable crossings. |
Cost of crossings will be borne by the renewables developer. No detailed assessment required. |
| Increased difficulty of access at cable crossing points with existing/planned interconnectors |
Export cables (operation) |
Increased maintenance costs for interconnector owners; loss of revenue for asset owners; loss of revenue for dependent businesses/customers |
Crossing agreements will generally make offshore energy developers liable for additional costs incurred by the existing asset owner. No detailed assessment required. |
A.11.4 Scoping Methodology
The spatial overlap between DPOs and existing/planned/potential power interconnectors to be assessed, once DPO areas are available.
A.11.5 Assessment Methodology
If a significant interaction between DPOs and existing/planned/potential power interconnectors is identified through scoping, further consideration will be given to the potential socio-economic impacts in consultation with the relevant owner/promoter.
A.11.6 Data Limitations
As noted above, there is no agreed methodology for calculating the economic value of subsea power cables. The capacity of subsea power interconnector cables may be used as a proxy for the economic value and intensity of activity for this sector.
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