Scottish Marine and Freshwater Science Report Volume 2 Number 13

This report describes the process employed by Marine Scotland to identify strategic search areas for future commercial scale offshore wind developments in Scottish Territorial Waters (STW). It also presents the first discussion of the development potential outside STW out to 200 nm


The Scottish Government has set a range of challenging targets for energy and climate change. These recognise the potential to take advantage of the extensive marine energy resources (wind, wave and tidal power) available in Scottish waters and include meeting at least 30% of total energy demand from renewable sources by 2020, incorporating:

  • 100% of electricity demand from renewables (31% by 2011)
  • 11% of heat demand from renewables
  • 10% of transport fuel from renewables

In addition, the Climate Change (Scotland) Act 2009 sets statutory targets of at least 42% emissions cuts by 2020, and at least 80% by 2050.

To assist in meeting these targets, a Sectoral Marine Plan for Offshore Wind Energy in Scottish Territorial Waters (Blue Seas - Green Energy) sets out the Government's vision for developing offshore wind energy up to 2020 and beyond and has identified short term development sites for offshore wind up to 2020, with a potential to deliver almost five Gigawatts ( GW) of electricity generation capacity; and a further 25 areas for further exploration beyond 2020. Currently, up to 10 GW of planned development is in progress at offshore wind sites in Scottish Waters, divided roughly equally between Round 3 sites and sites in Scottish Territorial Waters ( STW).

The Sectoral Marine Plan for Offshore Wind Energy in Scottish Territorial Waters (The Plan) was initially informed by Strategic Environmental Assessment, which allowed environmental considerations to be 'frontloaded' in the plan-making process. To further formulate The Plan, a series of options were identified, where it initially appeared that feasibility for offshore wind energy could be explored further. Firstly, the ten sites within STW holding 'exclusivity agreements' from The Crown Estate were identified as short term options. Secondly, mapping systems were used to consider where development could be technically feasible over the medium to long term. Several considerations were considered relevant at this stage - Wind Resource; Water Depth; Ports, and Grid. Thirdly, having identified the overall scope of the Plan as a whole, further analysis was undertaken to identify suitable areas for development in the medium to long term. This information was used by the consultants commissioned by The Scottish Government to develop the Plan and the associated Strategic Environmental Assessment to map zones of broad environmental sensitivity and technical issues using The Crown Estate's Marine Resource System ( MaRS). The Scottish Government's consultants were granted access to use The Crown Estate MaRS software to carry out their assessments. The consultants applied a system of scoring and weighting of information held in MaRS to produce graduated maps of the least to greatest technical, and subsequently environmental, sensitivity.

The MaRS system is a powerful tool for the handling and integration of a wide range of spatial data referring to environmental and technical factors that can influence the development of offshore wind energy (and other activities). The integrated data are presented as spatial models which map the constraints applying in potential development areas. In order to apply the MaRS tool, it is necessary for the user to make a number of decisions regarding the data to be included in the models and the way in which the data are to be handled.

It had been suggested by stakeholders that the Draft Plan gave insufficient attention to the interaction of potential windfarm developments with some existing activities, such as conservation areas and fishing grounds. Marine Scotland therefore undertook a sensitivity analysis of the spatial modelling process to explore the sensitivity of the outcome of the MaRS modelling undertaken as part of the development of the Draft Plan to the underlying decisions made during the MaRS modelling. Such a sensitivity assessment was consistent with procedures used in the MaRS modelling to identify potential development areas in the context of the Scoping Study for the Saltire Prize for wave and tidal energy projects.

The sensitivity analysis of the output from the spatial modelling that had been used to develop the proposals for medium term wind farm development in STW showed that the conclusions were sensitive to technical factors, such as the categorisation of data layers as representing complete (exclusion models) or partial (constraint models) constraints on development, the weighting applied to the layers, and the classification system used to create the scores. However, the degree of sensitivity differs between sea areas.

The sensitivity analysis noted that improvements in the available data had occurred since the Draft Plan had been prepared. For example, European Seabird at Sea ( ESAS) data are now available in a compiled form suitable for inclusion in spatial modelling. Other data layers are likely to be updated and improved during 2011 and 2012. The sensitivity analysis concluded that it was likely that the data available by 2012 should allow a more robust analysis of the medium term opportunities for wind farm development. The executive devolution to Scottish Ministers of responsibility for planning (and licensing) in Scotland's seas from 12 - 200 miles in 2009 through the UK Marine and Coastal Access Act suggests that an integrated wind farm development plan covering STW and more offshore areas should be considered.

The sensitivity analysis concluded that, as additional data and monitoring information, and improved data handling procedures, become available, these should be incorporated into the emerging iterative marine planning process, as applied to the medium term options for wind farm development in STW, and to opportunities further offshore.

A process was therefore put in place by Marine Scotland to develop a Scoping Report for the potential for offshore wind development in Scottish waters out to 200 nautical miles. It is intended that that this will inform the marine planning process by leading to the development of Regional Locational Guidelines for offshore wind development, which in turn will be the basis for an SEA to cover wind farm development in Scottish waters.

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