If you have version 3.58 or later of the HEM firmware (unrelated to Vera's firmware), it supports the ability to report in real-time whenever there is a change in the energy consumption. It generates a report for Vera whenever there is a change.
For versions 3.57 and lower, the only way to get real time energy reporting was to have the HEM send Vera reports constantly, whether or not there was a change. This required powering the HEM with USB power. So we recommend using the USB port on the HEM to upgrade to firmware 3.58 or newer, as per the instructions on aeon-labs.com
There have been reported issues with HEM firmware less than 3.61. If you don't have 3.61, download this file (link to come)