Grid-tied
Panels feed a grid-tied inverter, which sends power into your house and, if allowed, the grid. There is no battery.
Grid-tied inverters have a safety feature that shuts them down when the grid goes off. This stops them pushing power into lines where a worker might be repairing a fault. The result is that a plain grid-tied system gives you no power during load-shedding, even in full sun.
It suits people at home in the daytime who want to cut the grid power they use and do not need backup.
Hybrid
A hybrid inverter takes power from panels, a battery and the grid. When the grid fails, it can disconnect from the grid and keep supplying the circuits you chose, using the battery and the panels.
This is what most South African homes now choose to get through load-shedding. It works with the grid, so it still counts as grid-connected and normally needs registration with your electricity supplier.
Off-grid
An off-grid system has no link to the supplier's network. Everything comes from panels and batteries, sometimes with a generator for long cloudy spells.
It suits places with no grid supply. It needs a bigger battery and more panels than a hybrid system for the same house, because there is nothing to fall back on. Eskom says fully off-grid customers do not need to register, but must be able to show that they run independently.
Quick comparison
- Grid-tied: no battery, lowers daytime grid use, switches off in a blackout.
- Hybrid: battery plus grid, keeps chosen circuits on during load-shedding.
- Off-grid: no grid at all, so it must be sized for every day of the year.
Which one fits you
If load-shedding is your problem, you need a battery and a battery-capable inverter, which means hybrid or off-grid. If you only want a lower daytime bill and your outages are short, grid-tied may do. If you have no grid connection, off-grid is the only option.
Also think about growth. Some grid-tied inverters cannot be given a battery later. Ask whether a system can be extended.
Questions to bring to a quote
Ask which circuits stay on during an outage, how long the battery will last on them, and who registers the system. Ask what happens at night after the battery runs low. A clear answer in watts and watt-hours is a good sign.
Also ask about the day the grid comes back. A good hybrid system switches back quietly and recharges the battery without tripping your DB board. Ask the installer to explain what you will see on the screen or app, so a normal changeover does not look like a fault.
None of these choices is permanent. Many homes start with a hybrid inverter and a small battery, then add panels or battery capacity later. Ask whether the inverter you are quoted can take that growth, and what the limits are.
The job behind this: Solar PV systems.