I live in Alabama, where not only is net-metering not offered (charges $.12 for electricity and power company pays $.03 on excess generated), but the power company also charges $5/month per kilowatt of solar installed, on top of the usual $14 base fee to be connected. A 5kw solar system would mean paying the power company an extra $300 per year--for what? In the face of such punishing disincentives, solar is basically non-existent in this state. Nevertheless, I would like to consider, and would like some advice, on taking most of my condo off grid. I would need help sizing such a system, and pricing it out. What I imagine is this--building a solar system capable of running everything except my ac/heatpump and my electric dryer. Everything else, fridge, lights, sockets, washer, TV, computers, etc. would run on pv and batteries. My tankless water heater and stove are gas (though with some minor electric draw too). Three questions: how feasible is this? How would I size it? How much would it cost? I would save around $300/year, needlessly paid to the power company, but obviously, I would have to have some battery power as well for evenings and mornings. My power bill--in months without heat or a/c tends to run about 450kwh/month, but I could probably bring that down with new washer. Everything else here is pretty energy efficient. Thoughts or advice about where to start?

Start by reading how the Australians are dealing with it:

http://onestepoffthegrid.com.au/

Grid retail in Australia is 3x what yours is, and the net metering deals even worse, with even higher fixed fees in many areas. But their cost of solar is lower than the US average.

The additional costs of the batterys & control hardware necessary for an isolated fully off-grid system has a lifecycle cost above 12 cents/kwh even after the 30% federal tax credit, but that won't always be the case. Costs are continuing to fall, but it's going to be awhile before the financial rationale in AL is as high as it is down-under.

In Nevada it would be illegal to do what you're proposing. A grid-attached house there is explicitly disallowed from having an off-grid portion powered by a local generator or PV system. Check with local regulators as to whether or not similar restrictions apply to you.

I'm not hopeful that AL will develop a more distributed-solar regulatory environment any time soon, but that's really up to the local drivers for change. When outright grid-defection becomes financially rational that might change, but there's a reason AL is 41st in the nation on solar development despite favorable sunshine levels.

https://www.southernenvironment.org/the-state-of-solar

I guess you can start by lobbying your state legislators.