If you are on PGE tou-c, the difference in price between peak and non peak is so small, I have never worried about changing my usageI am in a similar situation, would like PW, but just too hard to justify the costs. I thought about doing just a single, like you suggested, but decided at this point it was much easier to adjust my usage during peak hours. We have had maybe 6-8 power outages in over 10 years, most of those were resolved within a couple hours, so not much of a need for backup power. I have an older solar array that is just over 10 years old, so plan to revisit the PW in a few years. At that point It might be worth while to replace my old system and add the PWs.