> The next thing you need to know is that renewable, whilst mostly very flexible
"Flexible" is an interesting word choice. Consider wind, for example. A 20 mph wind has 8 times as much power as a 10 mph wind, at 30 mph it's 27 times as much power. You can't control how much wind there is. Similarly, we might not realize it since our eyes measure brightness on logarithmic scale, but a cloudy day has 95% less solar energy than a sunny day. Most people would probably call this "unpredictable" or "unreliable" rather than "flexible".
On the other hand, the operators of a typical small natural gas plant with 4 generators can choose to run anywhere from full throttle on all four to just one at half throttle.