How much are you guys saving off your normal electric bill.
For me with SRP, an 8 kW system would have costed $16 K after rebates, but only save me $500 per year. I don't use that much electricity to begin with, so maybe it's just me. SRP is not solar friendly. The Tesla people told me that the power packs weren't going to help save money as they were mainly for backup power. Their on-line calculator was not sophisticated enough to factor load shifting into the equation. Even their solar calculator had serious bugs - no wonder the unit is struggling. With $2/W installed, they should be doing a lot better.
I'm on track to only spend about 800-$900 for the year with SRP, when my annual spend last year was around $3200 (includes about 500-600 kWh's of charging my wife's volt each month). This cost reduction is only possible with the Powerwall to zero out peak usage on the solar plan. Suddenly SRP seems more friendly when I can be on the most aggressive solar demand plan, but use zero peak demand and zero peak rate kWh's - and otherwise only consume off-peak power at just about the nations lowest off-peak rates - as far as I can find. Although, my system wasn't up and running until after peak summer, so far all my actual numbers numbers have come in better than my conservatively modeled estimates to calculate savings and payoff. (oh, and this is with only a 4.1kW PV system, I put the money into four PWs and took advantage of the SRP battery rebate - given the small PV system I have the expectation in peak summer I'll need the weekend to get the PWs fully recharged when needed).
When I replace about 80% of my driving next year with an second (full) electric car, vs the miles I currently drive in my old truck - that should save me another $2500-$3000 annually on gas, vs compared to what the cheap off-peak electricity will cost me. All of this "saving" was totally impossible for me to do with solar, from an initial cost & pay-off perspective, until the PWs became available in the SRP area this last year. So you are right that SRP was very unfriendly prior to these large battery systems being available, batteries with relatively sophisticated scheduling/mode capabilities (could still improve though) to manage peak loads.
I'm pretty satisfied with the savings and the pay-off rate at this point.
I never use my PW in backup mode, I simply set the reserve during off peak to 50%, and can usually keep it around there on average and still cover peak periods (except for a month or two during peak summer where I'll have to use the whole capacity) - so technically I do still have it for back-up most of the time, but I would have never bought the PWs just for backup. My SRP supplied power has been very reliable. One, maybe two noticeable very short outages (1 minute or less once, and once for a couple hours when a van hit a power line) in 3 years in my Current home before I installed solar - so backup mode did not factor into my calculations for purchasing a PW.