In my irregular review of the current electrcity rates I decided that it was time to switch to a time of use plan. The daily charge is lower, the solar feed-in higher, and while the peak rate is higher, that is only six hours of the day with the off peak rate being much lower:
| Previous | New |
|---|
| Daily charge | $1.08/day | $1.03/day |
| Peak rate | 27c/kWh | 29c/kWh |
| Off-peak rate | N/A | 17c/kWh |
| Solar rate | 4c/kWh | 6c/kWh |
I could possibly pull the data form Home Assistant or from the Enphase portal, but through my energy distributor I can download a CSV report of my usage going back years. I don’t recall the exact format but this one is in one day per row, then with the usage (as reported/charged by the meter) in half hour blocks.
Calculating what my bill would have been for the past few months showed that I would have paid at least 20% less, so I updated my plan.
I now needed to work out how to have Home Assistant split the power usage and cost between peak (3PM to 9PM) and off-peak (all other times). I quickly learned about the Utility Meter integration and I followed this video/post to get it set up.
This is when I encountered a problem in Home Assistant that was not easy to figure out. Most of the time Home Assistant works and does what I want because I am not doing anything unusual, but when you hit that unusual case it is quite painful…
What was I trying to do that was unusual?
Back when I configured the energy monitoring I set up two sensors, one for import energy and one for export energy. It is these that the energy dashboard uses and it is against those that the long term history is stored.
Not that I had split the import sensor into two (peak and off-peak) I could add these to the energy dashboard and set their appropriate rates, but if I removed the existing import sensor then I would lose the history from that sensor. I couldn’t have the existing sensor and the new sensors in the energy dashboard as then it would be reporting double.
I wanted to keep the existing sensor, but somehow transfer its history over to the new peak sensor. This is apparently possible to do with some strategic renaming of the sensors, but despite following different sets of instructions I couldn’t get it to work. The more common instructions appear to now be incorrect due to changes of how renaming sensors will also move around their history.
I spent more time that I wanted reading through reddit and forum posts, but in the end I worked out enough about how the long term statistics tables work to be able to copy all of the history from the existing import sensor over to the new peak import sensor, so now I have graphs that show two shades of blue:
Where this will be more useful is in the longer term views:
Of course there is still the question of why don’t I switch to Amber to get the variable wholesale rate? At this staged I am not comfortable making that leap, what would make me more comfortable is being able to get a few months of historical price data that I can them apply to my actual usage…
