>>RobinL+(OP)
I think one of the most important elements is buried - electricity pricing is uniform across the entire UK. That seems nuts to me, and incentivizes building in locations that are less useful - it's likely cheaper to build in Scotland, higher production from more wind, you get paid more (for expected yield plus curtailment apparently), and you have less wear on the equipment when you adjust to lower output.
>>TylerE+mk
The US runs three major grids: East, West, and Texas. There's interconnections, but capacity is limited. Sounds like the UK is similar here with the bottleneck between Scotland and southern England.
Within the US grids, there's really subgrids with interconnection and bottlenecks, too, but those interior bottlenecks aren't brought up as often as say overnight wind production in Texas being over local demand as well as interconnect capacity.