http://cleantechnica.com/2015/08/10/adding-energy-storage-to...
You can add a battery backup system to cover night-time usage on your own home. The $10k battery system basically doubles the price. But since the solar panel's price just dropped by 50%... Cloudy days you might still be in a deficit.
What is so wrong with a mixed system that uses renewables where it makes sense and relies on other sources to fill in whatever gaps appear?