Coal fired power stations are often unavailable two months a year. Sometimes more, if you are talking about old and less reliable plant. There is a 10-15% average total down time for coal fired stations and around 5% for gas, combining planned and forced shutdowns. https://www.nrdc.org/experts/rachel-fakhry/myth-247365-power-plant
And we have an immense overcapacity of fossil fuel generation just to meet peak electricity demand. Which can be much more efficiently managed by renewables and storage.
We've managed that sort of unavailability of fossil fuel plant on power grids for decades and will manage well diversified solar, wind, hydro and battery storage networks just as well. We designed how power systems operate to accomodate the uncertainty and unavailability of fossil fuel generation. We'll do the same for a renewables mix. And, as @acorn points out, for a couple of decades more, at least, we'll be able to use fossil fuel (as well as existing hydro) in a firming role to manage renewables variability. After that period we should have a well enough diversified renewables network, increased hydro and battery support and improved transmission interconnection to provide reliable, across the grid, renewables power.
At least you can forecast wind and solar unavailability. In my experience even planned fossil fuel shutdowns often over-ran and sometimes severely. And, obviously, coal fired unit and sometimes full station 'forced' outages or sudden shutdowns due to plant problems are unpredicted. And sometimes protracted, at a minimum usually lasting a day to days, sometimes months. We have a whole system of reserves and system wide maintenance planning geared up to manage the unavailability of fossil fuels. We'll develop wind and solar forecasting systems (already have, but they will develop) and hydro and battery storage management processes and optimisations.
p.s. enjoyed the cartoons. Humour is often found in the absurd and the pictures those cartoons paint are absurd.
