An interesting analysis from ERCOT Texas for 15 February - how different energy sources performed. What is the most important piece is the Avg Capacity Factor column.
For example, nuclear has 5 GW max power and operated at this power for 80% of time (including all cold related issues).
Even coal and gas ("dirty but reliable") operated at their maximum power for ~60% of time.
PV and wind operated at their maximum power for 11-16% respectively.