Here's a solar mining farm tour: https://www.youtube.com/watch?v=GrQ3-q2K03Q

Generally, you won't find many off-grid solar mines. Too unreliable, and power cycling the ASICs does wear them out faster due to thermal expansion causing micro fractures in the silicon.

More common are smaller solar installations that are still attached to the grid. So you have backup power to keep rigs running 24/7.

When miners are calculating the breakeven time for purchasing an asic, they assume its going to run 24/7, they assume constant $/kwh cost, flat BTC price and they assume 4-10% difficulty increase each adjustment.

So right away, with an unreliable source that works 1/3 of the time on a good day, you're instantly uncompetitive with grid miners or off grid using reliable energy like burning hydrocarbons or hydroelectric generation.

These days, you're probably better off selling 100% of the extra power to the grid than selling it to Bitcoin.

But things can change. It could flip back to be more cost effective to mine than to sell energy to grid. Like it was in 2020-2021 post china mining ban.

But since your power bill is basically 0 or negative, just plug in an asic and run it on the grid 24/7. Install a custom firmware on it so you can underclock it to be more efficient with your "free" energy.