After years of policy focus on encouraging installation of solar panels, California now produces more electricity from solar power during daytime than it can use.  However, after the sunset when solar power generation is not possible, California must continue to burn fossil fuel to meet its energy need.  To meet its target of “Zero Emission” by 2045, California now encourages installation of energy storage system (ESS) to save the excess solar energy produced during daytime and use them later when the sun sets.  
Hence, the recent policy shift in California is to incentivize and encourage installation of ESS at home and business.  Major policy changes in this direction are #1) providing rebates or subsidies and #2) revising the electricity tariff schedule in which those that do not install ESS are penalized by paying higher electricity bill than before.   In designing the solar PV system, one must have clear understanding of these policy changes and energy usage pattern to build the most efficient and economical solar PV system for that client.