$200/kWh by 2019. Assuming that households consume between 30 kWh and 15 kWh electricity daily on average and you want to have storage capacity for 1/3 of daily electricity consumption to get wind or solar energy work, you need 10-5 kWh per household. That's $2000 - $1000 per household. If that battery lasts 10 years, its $200 - $100 per year. It's workable and scales if we are able to reuse lithium. When does that h…
That wouldn't work for much of the South where summer usage for a house can easily hit 100 kWh/day for air conditioning. The hottest part of the day usually starts at about the end of the prime solar hours. Plus you'll want massive overcapacity of your batteries as deep discharges drastically reduce their useful lifespan.
It should be noted that peak energy expenditure for air conditioning happens more or less at exactly the moment when the influx of energy from the Sun is also at its peak. That's, like, a gigantic hint that mother nature is dropping on you, hoping you'll notice it. The disease, and its cure, are gushing forth from the same place at the same time.
Probably most of the energy for air conditioning in the future will not come out of storage, but it would be produced at the moment when it's consumed, by solar panels or some other solar technology.