We tested the peak power consumption of a NAS at the wall during a run of CrystalDiskMark 5.0.2 as this version of the benchmark runs the read and write benchmark suites separately so it's easier to monitor what power the device is using during each function.
With an energy efficient processor and a pair of hard disks that have only a 5w average power requirement each, the TS-231P has pretty frugal power demands.