Over the winter break, I was surfing around online to see if there were any projects that allowed someone to pull metrics and perhaps even control the Tesla Generation 3 Wall Connector. A post on Tesla Motors Club forums showed that some preliminary API calls could be made, and at the end of the post someone commented that they have a dashboard setup using InfluxDB and Telegraf that queries the TWC. So I set about getting this setup and running.
After a deep-dive into learning about Telegraf, and a couple of false starts resolving issues, I finally got it working. The price/kWh is averaged out over my last three years of data to use $0.1085, given that my utility has a usage-based tiered pricing structure.

The Total Energy Cost is since August 2020, and as of this writing (1/1/2022), we have exactly 12,000 miles on the Model Y. Note that we haven’t only used our TWC to charge, as we’ve taken a couple of trips and charged on the road.
I think the next step is to setup this dashboard using the Grafana interface I have running locally for TeslaMate. The Cloud InfluxDB offering is slick, but I like keeping my data local/private.