That link is pretty silly:
> So nuclear plants, by and large, get the market price whenever they produce (which is most of the time) and this does not equal the average price as they will be producing a higher share of total production at times of low demand (and low prices), and a smaller share of total production at times of high demand (and high prices).
The assumption here is that the price is set by only demand rather than the combination of supply and demand. Under that false assumption, generating power when demand is lower (i.e. at night) is bad. But how much solar generation is there at night, and what does that change in supply do to prices if you make solar a higher percentage of the grid?
It does the oppose of this:
> whilst the capture price for solar is often higher than the average price (thanks to power demand generally being higher during the day)
Because solar generates only during the day, in order to supply power with solar at night, you would need it to oversupply power during the day and then pay extra for storage to resolve the undersupply it leaves at night. So once you have a certain amount of solar, you end up with lower prices during the day, when solar is generating a higher proportion of the power, and higher prices after sunset.
And solar is double screwed by this. Not only does it get the soon-to-be-lower daytime prices for all of its output rather than half, its output is further regionally correlated, so that on sunny days when its output is highest, even the daytime price is lower than it is on cloudy days, because higher or lower solar output is a cause of lower or higher prices, i.e. the daytime price anti-correlates with its output.