Solar & Home Battery Blackout Autonomy Calculator
Plan whole-home or critical-load battery storage runtime during Texas ERCOT blackouts, Florida hurricanes, California PSPS shutoffs, and Northeast winter ice storms.
Designing Grid-Tied Storage for Multi-Day US Blackouts
Critical-Load Subpanel vs. Whole-Home Backup
A single 10–15 kWh battery typically uses a 5 kW to 11.5 kW continuous inverter. Trying to start a 4-ton central air conditioner or 240V electric dryer during a utility outage can trip battery overcurrent protection unless you install a smart load-management relay or isolate high-draw 240V circuits onto non-backed-up main lugs.
CA NEM 3.0 & Texas Wholesale Export
In states with reduced export compensation like California's Net Billing Tariff (NEM 3.0), batteries shift midday solar production into high-priced 4 PM – 9 PM peaks—accelerating return on investment while simultaneously keeping emergency reserve locked at 20–30% for wildfire Public Safety Power Shutoffs (PSPS).
Frequently Asked Questions
Under Internal Revenue Code Section 25D, standalone home battery storage systems with a capacity of at least 3 kilowatt-hours (kWh) and paired rooftop solar installations qualify for a 30% federal tax credit on eligible equipment and installation labor costs.
Backing up essentials only (refrigerator, lights, Wi-Fi router, sump pump, and device charging — roughly 500W to 700W average) requires 12 to 17 kWh per 24 hours. A single 13.5 kWh whole-home battery provides roughly one full day without sun, whereas pairing 20–27 kWh with a 6–8 kW solar array enables indefinite daily cycling during sunny post-storm periods.
Standard grid-tied string inverters and microinverters automatically shut down during a utility blackout due to IEEE 1547 anti-islanding safety rules. To power your home while the utility lines are down, you need either battery storage with an automatic transfer switch / Microgrid Interconnect Device (MID) or specialized sunlight-backup hardware.