The arbitrage on that has to be pretty thin? If the pack cost X and had to be replaced after Y years, can you recover that from each day's electricity?
Personally I'm on the old feed in tarriff scheme which gives me a fixed price for generation, regardless of export or usage ...
Here in TX (somewhat unusual, granted) I pay about $0.05/kWh for the wholesale power and about $0.04 for the "delivery charges" i.e. being hooked up to the grid, etc.
The truly wholesale market tends to be $0.01/kWh any time other than 11am-7pm and anywhere between "some more" and "lots, lots more" than that during the 11am-7pm window.
At some point it starts to become more economical to install extra solar to make sure I never touch the grid during the day. And eventually as battery prices come down and homes get more efficient it also becomes more economical to install batteries and even more solar to not touch the grid at night.
This may not be how retail power is priced everywhere but I suspect that wholesale power is priced similarly in a lot of places that get some sun and some wind so long as you're not really, really remote. It'll be interesting to see how this all plays out over the coming 5-10 years.
Given the prices you pay and the low cost of solar it seems like it would make a lot of sense to install panels wherever possible.
There are over 8k hours in a year and solar typically yields about 20% of nameplate capacity in a year, so perhaps 2kWh/W. If you installed 1kW of panels you could expect to get 2000kWh of electricity.
At $0.25/kWh * 2000 kWh = $500 and that's about what it would cost to buy 1kW of panels. So your project, if installed cheaply enough, could probably pay for itself within two years!
Depends solar with storage is one of the better deals for utility if the system is utility controlled: since you have storage they can decide when to take your power. The big problem with wind and solar alone is when it is on it is on with no care about who wants power. If they can take your power when people want it not when you generate it that is big for them.
Of course the above requires a large amount of management. Right now it isn't worth their while to take your power that way. However this is an opening, an standard system so that the utility can automatically take power from little guys opens up a lot of opportunities that don't exists.
Note that you should expect to pay about $10 a month for the above even if you are self sufficient. It should be worth that to you just to have the peace of mind that comes from utility backup when something fails. You can get that down, but probably at the expense of more equipment than you should reasonably buy and so your equipment costs are subsidizing someone else who doesn't spend as much on equipment.
> pay about $10 a month for the above even if you are self sufficient
This arbitrage is looking worse all the time?
Given that power cuts happen only for an hour or so every few years, I'm happy to buy a couple of LED torches and deal with it. There seems to be an ideological bias to getting off the grid for no good reason? While remaining on the water, sewage and gas grids.
Personally I'm on the old feed in tarriff scheme which gives me a fixed price for generation, regardless of export or usage ...