A MAJOR plank in the argument for the Western Isles proposed electricity grid link is the effect on employment in the islands.

Your editorial cites a claimed figure of 3500 new jobs ("Doubt over isles green power cable must end", The Herald, March 31). This figure, which is found in the joint Scottish Government/Department of Energy & Climate Change (DECC) report, wildly exaggerates the likely effect on permanent employment of the new link.

The report calculates a figure of just over 3500 full-time equivalent jobs (FTEs) in 2030. However, while FTEs may at first sight appear to measure jobs created they are in fact a statistical construct that treats temporary (for example, construction) and permanent (for example, maintenance) jobs separately, and then adds the temporary and permanent FTEs together to get an overall figure. Of the 3500 FTEs nearly 70% are due to temporary jobs created while the wind, wave and tidal farms are being constructed. Fewer than 1100 of the FTEs were attributed to ongoing activities.

More than 80% of these ongoing FTEs arise from projected wave and tidal developments - 1000MW of wave capacity and 300MW of tidal. These projections for wave and tidal energy are highly speculative and the projects may well not materialise at all. The consultants stated that "wave and tidal technology is still at an early stage of development ... it is acknowledged that technical and commercial feasibility at commercial scale is still a number of years away". Even if these developments do eventually go ahead they will require additional grid capacity and are not relevant in considering the current proposal.

Wind farms account for the rest of the projected FTEs, amounting to fewer than 200 ongoing FTEs from 500MW of capacity in 2030. However, in calculating ongoing FTEs the consultants assume that a full-time job for 10 years equates to 1 FTE and, crucially, that wind farms will be operational for 25 years. So each permanent job has been credited with 2.5 FTEs, and 200 permanent FTEs equate to only 80 full-time jobs at any time.

The upshot is that the Scottish Government's own consultants' report projected fewer than 80 full-time jobs arising from the ongoing operation of wind farms in the Western Isles in 2030. That - not the 3500 FTEs - is the most that can be relied upon when considering the case for the new cable.

Andrew Bain,

1 Stafford Street, Helensburgh.