Search areas for offshore wind energy: scoping study

Executive summary

Around Scotland, there exists the potential to extract significant energy resources in the form of renewable offshore wind energy generation. Any expansion of offshore wind energy generation in Scottish waters requires the application of marine spatial planning, at a national, regional and local scale, to identify areas that may be suitable for the development of offshore wind projects.

As the first stage of the sectoral marine planning process for offshore wind, this scientific study identifies the initial Areas of Search, which are then subject to a process of consultation and assessment, in order to become Final Plan Options. These Options, once adopted, will outline the spatial footprint within which any future commercial scale offshore wind development (over 100 MW) should take place, in Scotland. This report describes the process to identify Areas of Search that contain the best resource and overall suitability for future development.

Identifying Areas of Search required a multi-criteria analysis to be completed. This analysis brings together multiple geospatial data layers, which depict both opportunity (such as average wind speed or existing grid connections) and constraint (such as fishing activity, shipping traffic or environmental sensitivities) into spatial analysis software where they can be combined and presented as one national map. The full list of data used in this analysis is contained within the report.

Each spatial dataset included in the analysis is standardised in terms of resolution (grid cell size), spatial extent and classifications (high, medium or low level of constraint). Each dataset is then given a "weight" value which determines how much influence those data will have in the resulting output. The chosen relative weights are based upon previously published information where available. Where information is not available the most up to date knowledge is applied. The analysis produces a map highlighting areas around Scotland where there is both available wind resource and lower levels of spatial constraint.

Spatial data that describes locations where no development should be considered, such as areas where existing offshore infrastructure (oil and gas or renewables) is already in place, were combined into a separate "exclusion" data set. This exclusion dataset was then used to remove areas from the multi-criteria analysis output.

The resulting output from these processes produces a map where broad areas of potential opportunity can be discerned. The map shows varying degrees of constraint that are generally higher in areas close to shore. Areas of decreasing constraint begin to appear as distance from the shore increases. Although water depth generally increases with distance from shore this was not considered as a hard constraint as the study includes the potential for floating wind technology, which is theoretically not limited by depth. From this output, six Areas of Search were identified

For these six broad Areas of Search, a single issue analysis was then applied in order to refine the Areas of Search further. This process allows individual spatial constraints to further influence the Areas of Search by specifically avoiding a spatial constraint, at a local level, that may not be clear in the national multi-criteria process. Data used at this stage included individual species fishing activity, combined shipping routes and marine nature protection designations.

This refinement process resulted in the selection of 24 distinct Areas of Search that will be taken forward in the sectoral marine planning process and presented, through consultation, to relevant stakeholders for comment and review. Figure 1 shows the initial broad Areas of Search and the resulting refined Areas of Search that have been drawn once the spatial extent of the single issue activities has been considered. Table 1 lists the refined Areas of Search and the Scottish Offshore Renewable Energy Regions ( SORER) that they predominantly occupy.