Thanks for the update
@bob_p !!!
I was modeling our usage for the first 8 months in the house (with a guesstimate for the other 4 months) to see what a free nights plan would look like... Currently, about 63% of our usage is during peak (9p-9a), and the range has been 61-66% during the 8 months (a bit lower in Aug-Sept, higher in winter) -- although since we are not on a TOU plan, we haven't paid attention to high draw use, such as charging the cars, which has been mostly during the day. I estimate our annual usage to be ~25MWh, and Tesla is estimating ~21MWh of annual generation.
The model shows that we'd be able to shift nearly all of our grid draw over to the free period (I assumed solar only generated during peak, although there would be a little generation in the mornings before peak starts). Solar should generate enough to cover the on-peak use, plus a surplus in nearly all months (only August would have a grid draw during peak -- a total of ~12kWh for the month!). Looks like our electric bills would be under $17/month -- mostly for the fixed fees. I did a sensitivity to see what it would be if we still drew 10% of peak use from the grid, and bills would average ~$42/month (with summer peak of $57).
So -- I really like the idea of the free nights plan. Should model better than net metering plans since we will still draw ~4MWh annually. And this model doesn't assume that we'd shift most EV charging to night time (we had a TOU plan in Arizona and very rarely charged during the day -- was easy enough to plan charges out; the only difference now is that we have 2 EVs instead of 1, and only a single wall charger -- but we should be able to rotate charging nights easily enough).
A couple other questions:
1) How do you set your PowerWalls in the Tesla app? I assume Time-based using the Cost Savings setting? What do you set for backup power reserve (I'm thinking we set it at 30% unless expecting a storm...)
2) Do you pay for CenterPoint delivery charges during the free nights window (the EFL labels vary -- some say yes, others say no...),
3) Do you mind sharing which free nights plan you are on? Looks like there are currently 4 plans avail for those of us in CenterPoint delivery area, but have different windows for "night" (I will need to model the plans since they have different fixed costs and rates)... I'm guessing you are with Direct based on the free window...
- Direct "Twelve Hour Power" - 9p-9a free (which is what I modeled for billing). EFL says no delivery charges during free period
- New Power Texas "Free Power Nights" 8p-6a free. EFL includes delivery charges during free period
- Reliant "Truly Free Nights" 8p-6a free
- TXU "Free Nights & Solar Days" 8p-5a