We're going to see a lot more of this down the line.

I'm vice-chair of the south planning applications committee on Highland Council and when they apply for a windfarm it's usually for a limited life, and there's planning conditions about restoring the land to its original state at the end but it's pretty obvious that the direction of travel is to keep upgrading them. That's why ScottishPower is pressing to streamline the planning process for existing windfarms.

But there are issues with upgrades, not least height. Over 150m they need a red light on the top of the tower, which makes them far more visually intrusive at night, so currently we're seeing a lot of applications for 149.5m turbines.