None of them require a power socket although the "elite editions" feature a docking system.
Elite Editions include a desktop dock and have a LED capacity gauge on the front and a lock indicator.
[2] The Essential Edition for MacBook Pro and Air has a USB 2.0 port and a capacity of 320 GB (298 GiB) and is available in gloss black.
[3] The Essential SE Edition for Mac has a USB 2.0 port and a capacity of 1 TB and comes in silver.
This specific edition has been marketed as a hard drive designed to extend the storage capacity of consoles such as the Xbox and Playstation.