Search areas for offshore wind energy: scoping study

Scoping study about identifying areas of search to potentially be developed into draft plan options for offshore wind energy in Scottish waters.

4. Opportunities for offshore wind

Once the exclusion and constraint models have been combined, broad areas, that offer the best opportunity and reduced constraint were selected by manually drawing polygons around areas of similar low constraint. These areas are purposefully large to ensure that no potentially suitable sites are excluded at this early stage of the process. Two large areas have been identified in the east coast, one in the south west and one in the north coast. Near Shetland, one area has been identified in the south east and one larger area to the north. All these areas contain the previously identified draft plan options from the sectoral plan for offshore wind. Figure 23 shows the resulting output that combines the exclusion model and the contstraint model as well as the broad scale AoS. At this stage, the selection of broad areas need not account for smaller exclusion areas as these will be further analysed to avoid overlaps.

This process established a multi-criteria baseline which identifies potential opportunity and constraint at a national scale. Obvious areas of high constraint or exclusion areas are easily identifiable and this information is used to define the broad areas. Similarly, areas of opportunity can be presumed to contain less constraint and would encounter less issues in terms of any future development. As this process has considered many different aspects, a further refinement process, applied to the selected areas, can focus on specific issues in more detail. The next stage involved an examination of a selection of relevant spatial layers that were overlaid with the broad areas of search to assess, in detail, the spatail overlap with these activities and to refine the broad areas accordingly. This included layers that depict the activities and users most likely to generate interactions that may conflict with any future development. Section 6 describes this process.

Figure 23: Overall constraint, all themes equally weighted, and exclusion areas with the broad AoS. © Crown copyright and database rights (2018) OS (100024655).Table 3: AoS numbered, area in km2 and SORER area occupied.

Figure 23: Overall constraint, all themes equally weighted, and exclusion areas with the broad AoS. © Crown copyright and database rights (2018) OS (100024655).Table 3: AoS numbered, area in km2 and SORER area occupied.

Table 3: AoS numbered, area in km2 and SORER area occupied.

Name Area km2 SORER
1 7953 North
2 3884 North
3 20590 North East and North
4 13992 North West and North
5 12862 East and North east
6 5655 West and North West

4.1 East Coast . Including SORER Areas North, North East and East

The east coast of Scotland is host to a number of operational and consented offshore wind farms. The first test site to be installed in 2007 was the Beatrice demonstrator project which allowed evaluation of the feasibility of building wind generating structures in depths of 45 m at more than 20 km from the shore (Repsol Sinopec, 2017).

The east coast offers plentiful wind resource as well as conditions of relatively low wave regime, suitable substrate, and depths where current seabed installed technologies can be developed. This is reflected in the large amount of area that this study has identified as potentially suitable for development which will be narrowed down to focussed options that minimise interaction with other users. Currently installed developments occupy the areas closer to land in depths of up to 45 m.

There is generally a marked decrease in constraint as the distance from the coast increases. Two large AoS have been identified that show broad suitability. The highest constraint level is within 30 km from the shore and is mostly composed of Industrial activities like fishing and shipping. Nature protected areas and sea leisure activities contribute also to the cumulative constraint in the Firth of Forth. East of the Firth of Forth developments, at approximately 120 km from the shore there is a notable decrease in relative constraint south of the areas covered by the helicopter transit lines. The inner Moray Firth and the Moray Coast show a high level of constraint relative to areas nearby. The fishing activity and Special Area of Conservation ( SAC) designated for the protection of bottlenose dolphin combine to make these two areas unattractive from a consenting point of view. Areas north and south of the existing Moray Firth offshore wind developments show some opportunity although those closer to shore may be hampered by visual impact issues. Further offshore the constraint level shows a gradual decrease with distance but helicopter transit lines, areas of fish sensitivity and offshore fishing activity contribute to some patches of higher constraint.

Different fisheries overlap at different distances from the shore. The scallop fishery shows activity up till 150 km, the nephrops and whitefish fisheries extent further offshore and present areas of interaction with the AoS at some distance offshore. The refined AoS will take into account the fishing activity that occurs further offshore.

The oil and gas industry infrastructure is an important aspect of the North Sea. AoS 3 overlaps with a cluster of infrastructure at its eastern limits. These overlaps will be addressed when the AoS are further refined. The helicopter transit lines to and from the North Sea oil and gas locations are an essential inclusion into the suite of likely constraints. Their effect on the overall constraint can be seen emanating from the east coast of the mainland and Shetland and extending towards the oil and gas fields located further offshore.

Existing wind leases and areas of search in the Moray Firth and the Forth and Tay area have been included into the exclusion layer.

4.2 North Coast. Including SORER Areas North and North West

The north coast of Scotland presents some good areas of opportunity. The combination of grid connection, good wind resource and appropriate depths in an area with a low population makes this an attractive choice for development. A busy shipping lane crosses the north coast through this general area. This shipping lane traffic is composed predominantly of hydrocarbon transporting tankers, fishing vessels and cargo vessels. Sailing vessel traffic is also conspicuous around this location but in lower densities and generally closer to the coast. The AoS selected stretches eastward towards Orkney and straddles its west coast. A relative increase in constraint can be seen directly west of Orkney due to an accumulation of activities.

The AoS extends also towards the North of the Minch. This is a challenging environment for any offshore energy project, however the resource and depth as well as the areas relatively free from shipping and fishing make this a possibility for developments.

4.3 West coast . Including SORER Areas North West and West

The west coast is relatively constrained particularly in the Minches. The cumulative overlay of the fishing and shipping activity together with protected nature conservation areas, including a large SAC for harbour porpoise, account for this. This analysis suggests that consenting a farm in much of this part of Scotland could encounter a significant amount of obstacles.

The southern AoS that has been identified as containing a large area of relatively low constraint spans from west of Islay northwards to the southern tip of the Hebrides at the height of Barra. This AoS extends outwards from the 12 NM limit and contains a moderate amount of constraint throughout. Sites within this AoS would also present challenging conditions to developers; as well as high potential generation if those challenges were met. The north section of this AoS lies mostly over hard substrate, the cost of seabed attachment would have to be balanced against the benefits from the exploitable resource.

4.4 Orkney and Shetland. Including SORER Area North

Around Shetland the accumulation of fishing and shipping activity overlaid by the oil and gas activity and the helicopter transit lines make for some constrained areas. In addition to this specific sites that see annual fish life history evens such as herring spawning add to the activity around Shetland. The south east of Shetland shows a relatively decreased area of constraint, and the resource and closeness of infrastructure could potentially be an advantage. Approximately 80 km north of Shetland a large AoS has been identified that, although relatively far away from land, presents a good level of opportunity with minimised constraint.

The AoS that includes the western part of the Orkney isles presents some constraint due to the overlapping of fishing activities and nature designated areas but there are patches of decreased constraint that could be exploited.


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