I think I can answer that, though I'm not a Pakistani but as a Nigerian in a developing country, you might also have a petrol generator for night times. But for the majority of people just having your phone and power bank charged for the night is pretty ok, a plus if you can keep a handful of bulbs on also.
For my experience a lot of installations really doesn't have much battery capacity cause batteries are pretty expensive at least here in Nigeria, but a lot of people are really happy with the system as long as they get electricity even if it's only during the day.
The difference between off-peak and on-peak rates there is about $0.21/kWh in the summer and $0.29/kWh in the winter, so assume an average delta of $0.25/kWh.
Assuming no solar panels, if you charge the battery on the grid at off-peak rates and discharge it completely at on-peak rates, you break even after using about 3200kWh. Assuming 2 kWh used every day during peak rates that's a breakeven period of 4.38 years.
Maybe my calculations are wrong somewhere, and I'd love to learn if that's the case.
I also acknowledge some big assumptions: namely, that you will always need to use all your stored energy day at the peak time (reasonable in the summer when the AC is running) and that you can use all your battery power for those loads instead of grid power. On the other hand electricity rates tend to go up over time and batteries last for years.
No I goofed a bit too, by assuming 2kWh used every day but $800 in installation cost (which is for 1kWh). Fixing that error increases the payback to 8.76 years/kWh of installed battery. But only if you assume rates don't change for all of those ~9 years.
But rates will likely increase. So will the delta between off-peak and on-peak rates. I think the true payback period is between 5 and 8 years.
Batteries are dirt cheap already and getting cheaper all the time. Pakistan would be buying them at the Chinese prices without a lot of tariffs or nonsense that might be misleading you into believing otherwise.
Think a bandwidth of 50-80$ per kwh cost levels for the manufacturer with a margin on top in a market where there's over production and prices are still trending down and margins are probably under quite a bit of pressure. That's the widely publicized cost levels for Chinese manufacturers that dominate the world supply currently. Some of the sodium ion batteries that are coming to market now are already at the lower end of that price bandwidth and could go to 10-20$/kwh over the next 5-10 years; maybe faster.
At those prices, anyone can afford plenty of battery to survive the sun not shining for days/weeks. Which in places like Pakistan would be redundant. It's far south and you can count the number of days that you shouldn't be wearing sunglasses outside per year on the fingers of one hand. Even when it's cloudy, there's plenty of light filtering through in that part of the world..
Prices you might be seeing in the US tell you more about the local politics there than the economics of batteries. The US has it self to blame for bad economics like that. Places like Pakistan aren't going to slow down because the US can't figure out all this new stuff. For them this is economic growth unlocked by vastly more energy than they've ever had access to. All they'll ever need basically.
Unless you are proposing the laws of physics are different in the US, this is just a matter of market friction and blockages from regulations and tariffs. You know, the sort of things nuclear bros dismiss with a wave of their hand?
Battery modules (not home scale, but utility scale) are around $50/kWh in China. If we assume a 20 year lifespan and 50% charge/discharge once a day, that adds (ignoring interest) $0.013/kWh to the energy cycled through the batteries (plus a small add from efficiency being not quite 100%).
This is quite cheap compared to (say) the fully loaded cost of energy from a nuclear power plant.
Smaller units will be more expensive per kWh, but not so enormously so as to render them impractical. And they will get cheaper quickly like all electronics do.
For $800 you can get a complete 2kWh system, including cells, inverter and panels shipped to your home in Europe, so if you're paying more than that for half the storage either your government or contractor is fleecing you.
I can confirm that prismatic 1kWh LFP cells cost ~$60 in single digit numbers.
You can order 2kWh of plug-in-ready battery for 400€ or so on Amazon. That's single digit cents per kWh over the lifetime of the battery. Bigger systems are cheaper.
They can be depending on your needs. Lithium iron phosphate batteries are pretty cheap for their capacity. If you build your own power station with them you'd be surprised how far your money goes.
In Australia, if you have the space for rooftop solar, it's far cheaper in the long run to buy solar+battery. We did the math for our household and even if grid prices are stable (which they aren't, they're fast increasing) we're still going to make money back on the investment in less than 4 years.
Granted this includes a government rebate for the battery, but overall the prices have plummeted. Any government that isn't pushing for renewables and energy storage at this point is actively working against it's citizens.
No, and once the Solar Sharer scheme kicks in it'll be very helpful in avoiding leaning too hard on the grid in the evening after rainy or overcast days.
It's a fantastic way to solve oversupply; give it to everyone, including those who have batteries in areas where the weather restricts solar output.
