Battery Storage
Solar battery storage systems store excess electricity produced by solar panels for later use — typically for evening consumption when panels aren't generating, for backup power during grid outages, or for demand charge management in commercial applications. Battery storage is one of the fastest-growing segments of the clean energy industry.
Lithium-ion batteries (specifically lithium iron phosphate — LFP — and nickel manganese cobalt — NMC chemistry) have become the dominant technology for both residential and utility-scale storage due to their high energy density, long cycle life, and rapidly falling costs.
Residential Battery Systems
Popular residential battery systems include Tesla Powerwall, Enphase IQ Battery, LG RESU, and Franklin Electric aGate. These systems typically:
- Store 10–27 kWh of usable energy (per unit)
- Deliver 5–10 kW continuous power
- Achieve 90–95% round-trip efficiency
- Last 10–15 years (3,000–6,000 cycles to 80% of original capacity)
A single Powerwall (13.5 kWh) stores enough energy to power an average US home for 8–12 hours of moderate consumption.
Commercial and Utility-Scale Storage
Large-format battery energy storage systems (BESS) are deployed at commercial sites and utility substations in MW-scale containers. Applications include:
- Peak shaving and demand charge reduction
- Frequency regulation grid services
- Solar self-consumption optimization
- Time-of-use rate arbitrage
Storage Economics
Battery storage economics depend heavily on local electricity rates, utility tariffs, incentives (30% ITC applies to storage paired with solar), and the specific application. Demand charge reduction provides the strongest economics for commercial customers with high peak demand charges.