Battery storage went from optional to essential for California solar homeowners when NEM 3.0 took effect in April 2023. Understanding why — and which batteries work best — helps you make the right decision.
Why battery storage is essential under NEM 3.0:
- Solar production peaks midday; electricity use peaks in the evening (4–9 PM)
- Under NEM 3.0, excess midday solar exported to the grid earns only ~$0.02–$0.08/kWh
- Evening electricity from the grid costs $0.40–$0.55/kWh (PG&E/SDG&E peak TOU rates)
- Battery storage bridges this gap: charge during solar production, discharge during evening peak hours
- The difference in value: $0.08 export vs. $0.50 self-consumption = 6x more value per kWh stored
Typical CA solar + battery configuration:
- 8–12 kW solar array sized for self-consumption + battery charging
- 1–2 battery units (13.5–27 kWh) for evening discharge and backup
- Total system cost: $35,000–$55,000 gross; after 30% ITC: $24,500–$38,500
- SGIP incentive (if qualifying): additional $2,000–$13,500 reduction
Common CA battery options: Tesla Powerwall 3 (13.5 kWh, $10,000–$12,000 installed), Enphase IQ Battery 5P (various sizes), SunPower SunVault, Franklin Electric aPower. Most CA installers are Powerwall-certified. Battery inverters must comply with California's Title 24 and Rule 21 requirements.