A big game changer for the solar industry will be the ability for home owners to be able to readily store the energy generated by the PV panels during the sun period. There has been major development in this area, we have seen the rapid shift from the conventional deep cycle lead acid Batteries to AGM/GEL Batteries to current lithium-ion chemistries and the promise of further improvement including solid state cells.
Lithium-ion batteries have recently been the preferred choice of storage. The main drive is to improve on some of the deficiencies identified with the prior technology and to improve on the energy density of the batteries allowing greater energy storage ability, longer cycle life and safer cell.
A solar system capable of powering your entire house without the use of the utility can run a typical home owner JA $1.4M to 2.0M with limited battery storage. We find in recent years the self-enthusiast who desires to have these system installed without the exorbitant cost have turned to the world on electric vehicle and have been able to salvage the batteries from these units and retrofitting them for use as solar storage batteries. Tesla, BMW and Nissan leaf battery module are few of such batteries commonly used.