>>wind power is routinely curtailed in Scotland because at peak wind times there is more installed capacity than the grid can use,

This isn't completely true. If you look at where 'constraint payments' are paid in the UK a lot more go to Scottish farms, and hardly any to the modern offshore farms

Some of this is because the wind farms in Scotland are connected to the grid really badly. Grid infrastructure was not upgraded and so they need to be turned off more regularly. There is rumblings that this was done on purpose as the old old subsidy schemes paid a very high price to wind turbines if they needed to be shut off.

That incentive is gone in the more modern turbines so it pays for companies to ensure solid grid connectivity.