What a Section 36 consent actually covers, and why repowering hinges on it
If you manage a Scottish onshore fleet, you've already run into the term even if nobody ever explained it properly. Section 36 of the Electricity Act 1989 is the consent route for any generating station in Scotland above 50MW. It's the Scottish equivalent of what English and Welsh sites go through under the Planning Act 2008 regime for larger schemes, except the decision sits with Scottish Ministers rather than the local planning authority. The local council still gets a say as a statutory consultee, but they don't hold the pen.
In practice this means your original consent for a site built fifteen or twenty years ago was almost certainly granted by Scottish Ministers, with the application process run through what's now called DPEA (the Planning and Environmental Appeals Division). DPEA handles the procedural side: notifications, public local inquiries where one's called, the paperwork trail that eventually lands on a minister's desk for the actual decision.
Variation or fresh application: the fork that decides your timeline
Here's where it gets relevant to repowering specifically. Section 36C allows a developer to apply for a variation to an existing consent rather than starting a brand-new Section 36 application from scratch. If your repowering plan is modest, say swapping in a slightly larger turbine model on the same footprint with no meaningful change to blade tip height or noise envelope, a variation can move a lot faster than a de novo application. You're amending terms attached to consent that's already been through full EIA scrutiny once.
The trouble is that most repowering isn't modest. The turbine models worth installing today sit taller, sweep wider rotors, and often change the noise or shadow flicker profile enough that DPEA and the Scottish Government treat it as a new generating station rather than a tweak to an old one. At that point you're back to a fresh Section 36 application: full EIA, full consultation round, potentially a public local inquiry if objections are significant. That's a multi-year process, not a paperwork variation.
So the question "is this a variation or a new consent" isn't a legal technicality to park with your consenting advisor until later in the process. It's the single biggest driver of how long a repowering push takes at a given site, and it's largely set by how much the new turbine model's footprint differs from what's already consented, things like hub height, rotor diameter, and ground-level infrastructure like access tracks and hardstanding.
Why this matters when you're ranking sites, not just consenting one
A portfolio manager looking across fifteen or twenty ageing sites doesn't have the bandwidth to run a detailed consenting assessment on each one before deciding where to put effort. What you actually want is a rough sort: which sites have a turbine footprint close enough to a modern replacement model that a variation route is plausible, and which ones have such a dated footprint (short towers, small rotors, tight turbine spacing) that any sensible repower means a new Section 36 application regardless of what else is going on at the site.
That's a question about what's physically standing at each site today compared with what a viable repower would look like, which is exactly the kind of cross-referencing that normally means pulling up old O&M records, checking turbine model databases, and squinting at the latest site imagery to confirm nothing's changed since commissioning. Doing that by hand across a whole fleet is the bottleneck. Our repowering candidate list ages your fleet against current turbine footprints from one annual aerial pass and ranks sites by how straightforward the consent route is likely to be, so the variation-versus-new-application question gets answered for the whole portfolio at once instead of site by site.
If you're trying to work out which of your sites are worth a Section 36 push this year, that's the list to start from.