Hello,
What is the correct way to integrate a Power plug with energy consumption monitoring in the Energy Dashboard?
Currently, only my Aqara Smartplug is used, and I would like to integrate a Zigbee Energy counter that is connected to my main Energy meter.
Thanks!
Unfortunately, at the present time only Samsung smart appliances and a very few other devices can be included in the Energy dashboard. 
As you noted, the Aqara plug is one that works, no one seems quite sure why. Even the SmartThings brand models don’t show up. It’s a mystery. 
You can try asking support. If you get an answer, let us know.
https://support.smartthings.com/hc/en-us
Here is a previous conversation about the topic, FWIW:
I have an Aqara smart plug, but it doesn’t show up in Life- energy
Is there some step I need to take?
Could it also be used an an energy level trigger ST automations
I don’t know about the Aqara smart plug, but the Samsung SmartThings Outlets can be used as a trigger in routines, e.g. “Power Meter” “Equal or above” (or “Matches” “Equal or below”, “Range”) which I use to see if AV kit is being used or just in standby mode and can therefore be switched off until used. The Aqara might (should?) be the same.