Hotrod a Current Cost Envi with an ESP8266 and post energy usage and climate details to cloud services like thingspeak and firebase, process and serve data locally, and create custom notifications.
Since the Envi outputs serial ASCII data in XML format, it is easy to add an ESP8266 to its output port. It should also be possible to use a HopeRF transceiver module directly with an ESP8266 to emulate Current Cost transmitters and receivers.
Another useful addition is a voltage monitor circuit.
I added this (OLD!) code to github. It is still running since last Fall but is missing niceties like SPIFFS for configuration and static file serving. At some point, I may add that and change the Envi data parsing to handle multiple consecutive messages.