[manicdee]

A 100% renewable grid is possible by over-deploying renewable capacity, and providing time of production and time of use smoothing through storage.

Solar is particularly good at addressing daily peaks because those peaks generally happen during the day. Wind is good at relatively steady production around the clock because there is almost always wind blowing somewhere.

Coal is pretty terrible because it takes hours to react to changes in demand. This is why we have the term “baseload”: the rest of the industry must be highly dispachable to work around the high thermal mass (and resultant low responsiveness) of coal plants.

In addition coal plant tends to be large monolithic production, so the loss of one plant represents a significant proportion of supply. Coal is thus a net hazard to power reliability.