I’ve put together a few SmartApps, mostly based on other contributions on this forum, that will log power meter data (watts and sometimes kwh) to various power monitoring services/graphing services - ThingSpeak, SmartEnergyGroups (SEG), PlottWatt. I’m using these with my Aeon HEMv1, but they would likely work with any device that reports it’s capability as being a power meter.
I’m still having accuracy issues with SEG but have given up on resolving for now. They supposedly accept data in “Wh” not “kWh”; so I’ve tried multiplying kWh by 1000 before posting, but that makes their cost calculation widgets highly inaccurate. I really wanted SEG to work because they have the best widgets, but alas, I’m tired of debugging the problem with no help.
ThingSpeak and PlottWatt appear to be pretty accurate. PlotWatt takes watt usage and calculates cost based on your location, so if you’ve looking for accurate cost calculations, I’d start here. ThingSpeak is good for graphs, but you have to do lots of manual work to get accurate cost calculations (daily script to pull the data, calculate, then write back to another channel). PlottWatt is by far the easiest to setup; I haven’t been running it long enough to know the accuracy.
https://github.com/bdwilson/ThingSpeak-Energy-Logger (Example: http://bubba.org/things/ - some of these like daily/monthly calculations require some backend scripts to process the data daily, but you get the idea)
If you have issues/questions, it’s best to bug me on twitter.