Without the mains power connection it won’t be able to record ‘true’ power used, as with a simple current clamp only monitor the meter can’t account for the crazy power factor of many of today’s electronic devices.
However… There is a battery powered Aeon available (I think it’s V1) which doesn’t need the mains connection.
I have the Loop - a good bit of kit and is accurate in as far as the readings match up. I have the gas monitor as well as the electric monitor. The monitors themselves don’t need mains power - just the unit that plugs into the router. It shows current usage as well as having daily and weekly graphs of usage. It has a comprehensive dashboard but as has been said before it is not compatible with ST.
I use efergy engage with ST, @tonesto7 wrote a nice smartapp and device handler for it, so you get the current power usage and daily cumulative value in ST to do actions based on it, but the full historical reporting is on efergy’s site
It has the extra features of being able to identify your major power-consuming appliances individually so you can see where your electricity pounds are being spent. Also it has a built-in 433Mhz controller so it makes a very cost-effective way of on/off controlling of various appliances up to 1kW using compatible 433MHz plugs (around £10-15 a time, rather than the £30+ of a WeMo or the £40+ of SmartThings Outlet) … just bear in mind that it cannot directly monitor the state of the switches, but it can tell you the power being drawn if it has a high enough wattage to be detected via the current clamp.
I have written a DTH that allows me to poll the Smappee power consumption direct from ST via my LAN, and it has a great IFTTT integration too.
Would it be possible to have a copy of your DTH for the Smappe monitor? The ST approved one cannot be seen in ActionTiles becouse it fails to claim Capability “Sensor”