> You want to grab all you can during excess production/very low prices periods and then use that for the rest of the day.

Batteries help, but even that is limited in northern countries like the UK. If you look at the data, in July '25, solar produced 2.36 TWh. But in December '25, it was only 0.535 TWh: the output in summer is >4 times the winter output. So either you need to discard 75% of the electricity produced in summer, or you need truly gigantic batteries that store power produced in summer for winter. Both is not economical. Solar is far less efficient in the UK than in, for example, Florida.

In the UK wind contributes more to the grid that solar (not unexpected). Overall the issue with either or both is still that production varies widly over time including within a day.

With solar specifically you have the obvious day/night cycle, which makes storage required to make the most of it.