It's a mistake to assume energy source composition too. I would guess that a majority of mining is renewable right now (mining is a perfect sink of intermittent excess energy, and because its profitability is related to energy cost, renewables win). More so in the future.

The capital expenditure is sufficient that it still makes sense to run the miners 24/7 and not try to take advantage of cheap electricity - although that does matter somewhat when deciding where to place the data center.

This is true of pretty much every industrial process. The idea of running production only when the sun is shining to absorb excess solar seems like a universally poor idea.

Rarely industrial process can switch on and off randomly and still scale revenue linearly.

The capital expenditure argument makes sense when mining is the primary business. Using old and otherwise unprofitable (but cheap) hardware makes sense where there is intermittent excess energy.

Having cheap energy 50% of the time is still better than 0% of the time.

Of course, that goes without saying.