The drive comes with a power block that plugs into a wall outlet. It does not depend upon the USB connection for its power. The unit is a disk drive, not flash memory. I haven't tested USB 2.0 compatability, but it should work in a USB 2.0 port, but will transfer data at the slower USB 2.0 speed. It comes with what is termed a USB 3.0 cable, which as far as I know should also work in a USB 2.0 port.