@Devonkiwi @The_Sun

I'm guessing a bit but I imagine it's because most solar is “embedded”, that is connected to the local distribution network rather than the grid, and not metered in real time so not directly visible to the grid operators other than as a reduction in demand. That's not just domestic solar but also commercial solar field-scale farms.

AIUI, even some relatively large wind [¹] is like that, too. E.g., I think the Burn O'Whilk farm near me (9 x 2.5 MW turbines) is not, in the strict sense, grid connected.

Therefore, the actual percentage of renewables will be a bit higher than shown here.

@janrosenow

[¹] compared to domestic-scale turbines people have in their gardens and farmers have in their fields.