A home energy storage battery, or Energy Storage System (ESS), is a system that stores excess electricity for later use, usually from renewable energy sources like solar PV panels, but also by scheduling itself to store cheaper off-peak electricity from the grid.
A battery provides greater energy independence and control, allowing homeowners to use their own low-carbon energy, avoid high peak-hour electricity costs, and also to have a backup power source during blackouts.
Virtually all home batteries use lithium-ion batteries, integrated into compact all-in-one units with an inverter or as modular DC systems combined with hybrid inverters.