> idle SSDs

Bearing in mind that SSDs used in data centres (at least used to) not have much in the way of low power idlying mode like consumer grade SSDs do (due to laptop requirements).

Data center SSDs quote idle power much lower than active power, and lower than HDD too. Data centers care plenty about power consumption.

Good. The stuff I still deal with (older generation SAS2/3 gear) isn't that way. ;)