Scottish Marine and Freshwater Science Volume 3 Number 1: Scoping study for tidal stream energy development in Scottish waters

5 Opportunities for Tidal Stream Development in Scottish Waters

The potential locations for tidal stream energy developments are strongly limited to the locations where sufficiently strong tidal currents occur. These areas are confined to coastal and near shore waters where the large volumes of water involved in tidal fluxes are constrained to pass through firths and sounds (such as the Pentland Firth), or round headlands (such as off the south west of Islay). Suitable resource areas were identified through the resource assessments.

The tidal stream energy resource areas in Scotland, as indentified from the resource assessment, are:

A. Pentland Firth
B. Orkney and Westray
C. Sumburgh and Fair Isle
D. North Skye
E. South west Islay and Kintyre
F. Solway Firth

The geographical extent of these areas is large enough for there to be opportunities for fully commercial scale development of tidal stream energy projects. However, any development will have to take account of the constraints arising from environmental, industry and socio-cultural factors. The relative importance of these factors between areas is shown in more detail in the extracts from the combined models shown in Figures 9, 10, 11 and 12.

All the combined models indicate that the least constrained areas from environmental, industry and socio-economic aspects are South west Islay, northern parts of Orkney and Westray area and in the southern part of the Solway area. The details of the constraints in all the resource areas identified in this report will be presented in greater detail in Regional Locational Guidance.

No resource areas for tidal stream energy developments at this time have been identified outside Scottish Territorial Waters. Technical development has been targeted at situations of high tidal currents, to exploit the associated high power density. There has been some theoretical discussion of the potential to exploit the persistent, but relatively slow ocean currents present in some deep water channels, but no significant commercial interest has been expressed.

This analysis should not be taken to imply that there are no useful tidal stream resource areas elsewhere around Scotland. The identification of resource areas has been based upon tidal stream maps taken from the DECC Renewables Atlas ( DECC, 2008). The tidal stream information in that Atlas is presented as a grid of data, with cell size of 1.8 km. Resource areas smaller than this may well not be represented, and areas up to the scale of a few cells or immediately adjacent to the coast may be poorly represented. It is well known that there are a large numer of small areas around Scotland where tidal streams are at times powerful. These include areas at headlands, areas around sills at the entrances to sea lochs (and separating basins within sea lochs), and channels and sounds between islands and between islands and large land masses. Such areas will not have been captured by this scoping study, but in favourable locations may offer considerable potential for small (and perhaps medium) scale developments for testing or commercial purposes.

Figure 9 Combined restriction model for tidal stream resource areas, giving equal weight to the environmental, industry and socio-cultural themes.

Figure 10 Combined restriction model, emphasising the environment theme.

Figure 11 Combined restriction model, emphasising the industry theme.

Figure 12 Combined restriction model, emphasising the socio-cultural theme.