It turns out that a crucial part of the wind farm project is to connect Shetland to the mainland National Grid. However, this is not in the way I'd expected. I have to confess that I'd never come across the concept of High Voltage DC transmission. Now I come to think about it, we taught that power transmission is AC partly because it is generated as AC and mainly because it can be transformed to high voltage, low current to reduce losses. Here's the Shetland HVDC details. The page on HVDC points out that the technology only came of age less than a decade before my university studies which will explain why I missed it.
