[Buraksr]

I believe that what is happening is that the rated capacity of a power plant is its maximum output times its capacity factor. Say we have a solar plant that produces a maximum of 1 GW in optimal conditions with a .15 capacity factor. This plant is not a 1GW plant but a 150MW one.

In general fossil fuels have capacity factors around .55, nuclear about .9, hydro about .4, and solar is between .1-.3

So you can imagine a scenario where we have 200MW of natural gas and 200MW of solar, and a grid load of 300MW. The natural gas could produce 400MW, powering the grid alone. Similarly, we could have up to 1 GW of solar, more than enough. But the averages are what is important, and what we use in ratings.

These stories are mostly “feel good” and without meaning imo. We will hit 100% energy from renewables for x minutes, long before we have enough power for the grid. If we were trying to make all the renewables come online at once, you don’t actually need that much capacity to hit 100%. The capacity factor says we only need 1/5 of the grid as solar to hit “100%” renewables. The reason we haven’t is intentional, we want more consistent power from these typically inconsistent renewable sources.

[Buraksr]

I should have mentioned explicitly that:

average power = capacity factor * max power

Thus it is clear why nuclear is .9, it doesn’t vary much in its generation. The max is only a bit more than the average. Capacity factor is in some sense, but not exactly, the variability.