Core Knowledge

A system where the PV array powers a DC load directly, with no battery or inverter, so the load runs only when the sun shines (e.g., a solar water pump or vent fan).

An off-grid system not connected to the utility that typically uses batteries to supply loads when the sun is not shining.

A system connected to the utility grid through an interactive inverter, exporting excess power and drawing from the grid when needed; without storage it shuts down during outages.

Anti-islanding protection: it must stop exporting when the grid is down so it does not energize lines that utility workers believe are dead.

A grid-connected system with energy storage and an inverter that can operate both grid-interactive and in stand-alone (backup) mode during outages.

A condition where a distributed generator continues to energize a portion of the grid that is disconnected from the utility.