On-grid, hybrid, PV-diesel and off-grid

The four types

On-grid (grid-tied PV). Solar offsets what the site consumes while the utility is up. There is no ride-through: if the grid drops, so does the system. Sized against daily energy and whatever share of it you want solar to cover. Storage is out of scope beyond any life-safety requirement.

Hybrid (grid + storage). Solar and a battery alongside a working grid, sized so the chosen loads stay alive through an outage. This is the common choice where the grid is mostly reliable but not entirely.

PV-diesel hybrid. Solar and storage on a site that already runs a generator, on a weak grid or none. The point is rarely to remove the generator - it is to take it off the base load so it runs fewer hours and burns less fuel. The set stays as backup of last resort.

Off-grid (standalone). No utility supply at all. The array and the pack carry the entire load, every day, including the bad ones. These size the largest relative to the load, because there is nothing to fall back on.

What actually changes

The system type sets two things the engine cares about - whether there is a grid, and whether there is a generator - and those flow into the battery, the recharge check and the warnings. It is recorded on every saved sizing so a quote is never ambiguous about what was priced.

Picking the right one

If the customer has a generator today, it is a PV-diesel hybrid even if they hope to retire the set later: size it against how they run now. If there is no utility meter, it is off-grid. If they only want a lower bill and accept going dark in an outage, it is on-grid. Everything else is a hybrid.