Draft Sectoral Marine Plans for Offshore Renewable Energy in Scottish Waters: Socio - Economic Assesment

B10. Power Interconnectors

B10.1 Overview

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 existing OWFs). Figure B10 shows an overview of existing interconnector infrastructure in relation to Draft Plan Option areas. Information sources used in the assessment are listed in Table B10.1.

Table B10.1 Information Sources

Scale	Information Available	Date	Source
Scotland	Existing cables	Current	Admiralty Charts
Scotland	Power cables (submarine electricity cables)	Current	Baxter et al. (2011)
Scotland	Potential future subsea cable developments / reinforcements	2009	National Planning Framework for Scotland Annex National development 11 (Scottish Government, 2009b)

B10.2 Future Trends

The location of offshore renewables resources, often remote from locations of power demand, and the large proposed expansion of offshore renewables development may drive the development of an offshore grid network and interconnectors.

UKMMAS (2010) reported that over the period 2007-12 the Office of the Gas and Electricity Markets (Ofgem) provided for capital investment of up to £4.3 billion in the electricity transmission network, an increase of 160% over the previous 5-year price control period, with much of this investment planned for Scotland.

The Scottish National Planning Framework 2 (Scottish Government, 2009b) identifies 'electricity grid reinforcements' as one of the fourteen national developments essential to the delivery of the spatial strategy set out in the second National Planning Framework. The strategic grid reinforcements are essential to provide the transmission capacity necessary to realise the potential of Scotland's renewable energy sources, maintain long-term security of electricity supply and support sustainable economic development. This development would occur throughout Scotland, from the English border to the Shetland Islands and, in relation to marine power interconnectors, would include:

• Reinforcement of the sub-sea cable link between Orkney and the Scottish mainland; and
• New sub-sea cable links for the Outer Hebrides and the Shetland Islands.

B10.3 Potential for Interaction

Table B10.2 shows potential interaction pathways between power interconnectors and wind, wave and/or tidal arrays.

Explanation of column content:

Column 1: Describes the potential interaction between the activity and any renewable technology;

Column 2: Identifies the types of offshore renewable development (wind, wave or tidal) for which the interaction may arise;

Column 3: Identifies the potential socio-economic consequence associated with the interaction identified in Column 1;

Column 4: Indicates whether detailed assessment will or will not be required if activity is scoped in;

Column 5: Identifies how the socio-economic impact will be assessed.

Table B10.2 Potential for Interaction

1	2	3	4	5
Potential Interaction	Technology Relevance (Wind, Wave, Tidal)	Potential Socio-economic Consequence	Scoped in (√) or Out (X) of Assessment	How the Economic Impact Will be Assessed
Draft Plan Option areas and/or cable routes intersect proposed interconnectors	All arrays, export cables	Increased costs associated with new cable laying operations	√ - where Draft Plan Option areas or cable crossings intersect proposed interconnectors	-Consultation with industry to determine any potential developments for which cable routes might require extension or involve additional cable crossings; - If an interaction is identified, cost can be assessed based on average cost per km for relaying costs, based on ODIS information. See Section B10.4 for detailed methodology.
Cable crossings with existing interconnectors	All arrays, export cables	Additional costs to construct cable crossings	X - costs of crossings will be borne by developer.	Economic assessment not required.
Increased difficulty of access at crossing points	All arrays, export cables	Increased maintenance costs for cable owners; loss of revenue for asset owners; loss of revenue for dependent businesses/ customers	X - crossing agreements will generally make offshore energy developers liable for additional costs incurred by the existing asset owner.	Economic assessment not required. Qualitative assessment of potential issues undertaken (see Section B10.4)

B10.4 Scoping Methodology

B10.4.1 Draft Plan Option areas and/or Cable Routes Intersect with Proposed Interconnector Routes

Wind, wave and tidal array development in Draft Plan Option areas, and export cable routes from Draft Plan Option areas have the potential to affect future power interconnector routes, resulting in increased costs associated with additional cable laying distance to deviate around Draft Plan Option areas or export cable corridors.

For the purpose of this assessment, this potential negative effect was only considered to be likely where Draft Plan Option areas or export cable routes intersected with future planned or proposed power interconnector routes that were likely to be constructed after agreements to lease had been issued in relation to Draft Plan Option areas (assumed 2015) or after licence applications for array export cable routes had been submitted (assumed 2020).

Table B10.3 and Figure B10 show future planned/proposed interconnectors identified within this scoping exercise (source: Scottish Government (2012) and Electricity Networks Strategy Group (2012); Saunders et al. (2011); DECC Energy Networks Strategy Group Major Project Status Update ( DECC website).

Where the exact landfall points and/or route for a planned/proposed interconnector was not known, the spatial overlap with Draft Plan Option areas and/or cable corridors was assessed visually (as opposed to within GIS). The current project stage and earliest completion date of interconnectors was used to estimate whether consent for the interconnector projects was likely to be granted prior to lease agreements for Draft Plan Option areas (assumed 2015) and Draft Plan Option areas export cable corridors (assumed 2020). Using the assumption that any interconnector may take approximately three years to construct, any interconnector with a completion date up to and including 2018 would be consented prior to the assumed lease agreement date for Draft Plan Option areas (2015) and any interconnector with a completion date up to and including 2023 would be consented prior to the assumed lease agreement date for export cable corridors (2020). Using these assumptions, the following scoping method was applied:

• Draft Plan Option areas and/or cable corridors which are not intersected by planned/proposed interconnector routes were scoped out of the assessment;
• Draft Plan Option areas which are intersected by planned/proposed interconnector routes due for completion by 2018 were scoped out of the assessment;
• Draft Plan Option areas which are intersected by planned/proposed interconnector routes due for completion after 2018 were scoped into the assessment;
• Cable corridors intersected by planned/proposed interconnector routes due for completion by 2023 were scoped out of the assessment; and
• Cable corridors intersected by planned/proposed interconnector routes due for completion after 2023 were scoped in to the assessment.

The assessment has assumed constant prices in real terms based on 2012.

The results of the scoping exercise are presented in Appendix C10.

Table B10.3 Future Planned/Proposed Interconnectors

Project	Description	Current Project Stage*	Earliest Completion Date
Western HVDC Link	West Coast 1.8 GW High Voltage Direct Current ( HVDC) link between Hunterston and Connah's Quay in North Wales	Construction	2015
Eastern HVDC Link	1.8 GW HVDC link between Peterhead and Hawthorne Pit in Humberside	Optioneering	2018 (Q2)
Shetland HVDC Link	Island link connecting Shetland Islands to Moray Firth offshore hub	Design	2017 (Q4)
Orkney 132kV Subsea Link	Island link connecting Orkney and Pentland Firth Subsea Link	Design	2015 (Q4)
Western Isles HVDC Link	Island Link	Planning	2015 (Q4)
Hunterston-Kintyre 240 MVA AC subsea link	AC subsea link between Hunterston and Carradale in Argyll and Bute	Planning	2015 (Q4)
Caithness-Moray HVDC reinforcement	HVDC Link: from Caithness to the Moray Coast via the Moray Firth Offshore hub	Design	2016 (Q4)
UK-Norway NorthConnect	Interconnector between Norway (Sima and Samnanger) and Scotland (landfall Peterhead).	Co-operation agreement signed in February 2011	Expected to be operational before 2020

*Current Project Stage:

Optioneering: Transmission Operator believes that the need case is firm, number of design options provided for public consultation so that a preferred design solution can be identified;

Design: Designing the preferred solution into greater level of detail and preparing for the planning process;

Planning: Continuing with public consultation and adjusting the design as required through the planning process application process;

Construction: Planning consent has been granted and/or contracts have been awarded and manufacturing underway.

B10.5 Assessment Methodology

B10.5.1 Draft Plan Option areas and/or Cable Routes Intersecting with Proposed Interconnector Routes

For any Draft Plan Option area scoped into the assessment, it was assumed that the cost to the sector of having to 'detour' the future interconnector around the Draft Plan Option area could be calculated as follows:

Length of deviation (km) x average cost pipeline laying per km (£/km)

It can be noted that the length of deviation around wave or tidal arrays may be smaller due to the lower proportion of Draft Plan Option areas that would be covered by those devices compared to wind Draft Plan Option areas.

Currently there is still uncertainty surrounding the routes of the Draft Plan Option areas export cable corridors. This makes any assessment of the economic impacts of interactions between future interconnectors and cable corridors difficult. As such, a qualitative assessment of this issue was undertaken where possible interactions were highlighted by the scoping methodology and consultation with industry.

B10.5.2 Increased Difficulty of Access to Existing Interconnectors at Crossing Points

It is possible that export cable routes from proposed Draft Plan Option areas may cross over existing cables. While this does not pose any major issues during the construction phase (and the cost of the cable crossing will be transferred to the developer), the general proliferation of cables in the marine environment may increase the costs of maintaining existing cables in the future ( ABPmer et al. 2011).

A qualitative assessment of this issue was undertaken based on any areas of concern highlighted through consultation with the industry sector.