Earlier quoted context omitted.
Loads of on-shore wind is likewise not metered. If you own a hill top farm, especially if you have industrial electricity loads (e.g. milking cows, lighting barns full of hens) it makes loads of sense to buy a modest turbine and install it on a suitable rise, it won't pay for itself over night but it's very competitive with other farm investments and not correlated. If electricity prices go up the turbine is better v…
That seems very large - I can’t imagine plain farm owners could reach that kind of wind capacity, are you sure that’s accurate?
There's no central register of unmetered power generation, the assumption used is that if on a windy day mysteriously we're buying 25GW from the grid across the country, while on a similar but calm day it was 30GW that suggests 5GW of electricity is not being purchased when it's windy, implying 5GW of unmetered electricity supply from wind.
And there are presumably other embedded systems making up some of that 5GW estimate. Farms just seem obvious because 1) I've seen farms with wind turbines 2) They're industrial scale electricity users, often occupying terrain very suitable for a wind turbine