There are no exact specifications, but it will not be much different from other external hard drives. According to this, the power consumption will be between 2-4 watts under full load.

I can't give any figures on this either. But a new backup of 500GB, for example, took an hour.

I looked at my drive. There is no mention of power consumption either on the drive itself or on the packaging. But I suspect that the power consumption is negligible compared to a TV.