A very tiny % of solar panels are mechanized. That whole idea has mostly been obsoleted by increasingly cheap solar panels. Hydro obviously isn't worth running at exceptionally low prices in most cases as most hydro involves water storage –not run of the river – so it's better to use the water later. But hydro is usually dispatchable, so I didn't even mention it as it's really not in the same category as solar or wind. That said, even with hydro sometimes they'll run hydro plants for long periods at negatives prices. IIRC an example of this maybe a decade or so ago was a Quebec dam where so much rain had fallen they they needed to dump it through the turbines even though they'd pushed electricity prices negative, as it was cheaper to pay that price than have to use (and then repair) the emergency spillways (mechanically, the turbines had to have an electrical load on them or they'd overspeed).