In particular, one can calculate minimum base load and amortized base load.
Critical infrastructure informs minimum base load. For example parts of defense grid, AC when disabling it would kill people, medical systems, certain lighting, running and monitoring the power plants, certain kind of industrial cooling, mining safety equipment like air and gas pumps, certain sluices in regions with flooding.
More or less anything that if turned off would or could immediately cause a catastrophe.
Amortized base load adds some other things that just cannot be off for long or you incur huge restart or lack of function costs.
Examples would be microchip manufacturing, water treatment, key mass transportation, oil pumping and drilling.
A lot of amortized base loads are on week scale rather than day, so they tend to be reasonably solar friendly, but less wind friendly.
