I share the author’s concerns for off grid power use. 3 watts per drive (I assume a wall wart for a 3.5” drive) works out to 72watt hours per day. About 1/10th of a $200 solar panel. Double or triple that to cover batteries and electronics. Then you run into discontinuities in system sizing where you can’t easily add just one more panel. Conserving energy suddenly makes a lot of sense.

USB hubs with per port power control are the flying unicorn of hardware. Once in a while some vendor slips up and makes one, but by the time people figure it out the vendor has ended the model or replaced it with a different model under the same model number. It’s especially frustrating because many of the USB hub chipsets support the feature, but only if the manufacturer puts a switching transistor on each port. It literally would only cost pennies per port to have the feature.