The utility will jack up rates no matter.
I put in a small 4 panel 400 watt system with 1000 amp hour of batteries for nighttime. During daylight I run all excess solar power to household devices. At night the batteries store enough to act as a solar generator for power outages which are frequent. My wife relies on an O2 machine so backup power is important. I do NOT grid tie to the utility, I make sure to use all excess power after batteries recharge from overnight.
I just did a summary of the first 9 months of this year compared to last year. In 2013 I used just over 19,000 kwh in 9 months and this year over 2,000 kwh less at just over 17,000 kwh. It worked out to about 10% kwh usage savings. BUT my 9 months billing only saved $45.00 because of rate hikes. In reality I saved almost $300.00 over the period that I would have paid for the 2,000 or so kwh if I had used it from the utility instead of solar.
Hard to win, but you can get ahead.
The only way to “win” would be to go off-grid, but that means sacrificing some comfort and convenience in order to keep the cost of the system within any reasonable hope of ROI or approximation of affordable, given present technology.
NC doesn’t allow battery storage systems for on-grid houses with solar. My thought was to use it for emergency backup power, but that’s only possible with a totally separate solar and storage system. For instance, setting up a freestanding garage with solar power and battery storage, or having solar panels and batteries on a trailer like a generator. I believe there are actually units sold as solar generators that are set up in this manner, so NC must not be the only state with such a restriction.