These three terms come up so often that they get confusing, but the real difference is simple. It comes down to two questions: is the system connected to the utility's power lines, and can it store power for use at night?
| System | Connected to the grid | Battery | Works during a power cut |
|---|---|---|---|
| On-grid | Yes | No | No |
| Off-grid | No | Yes | Yes |
| Hybrid | Yes | Yes | Yes |
On-grid: the system most homes should choose
The system is connected to the utility's power lines at all times. During the day you use power from the panels; if they are not producing enough, the grid automatically makes up the difference. At night you use grid power as normal.
The advantage is that it is the cheapest option, because there is no battery — the most expensive component in a system — and it needs the least maintenance, because there are no parts that must be replaced as they age.
The one limitation you have to accept is that during a power cut, the system shuts down, as required by safety rules.
It has to shut down because, if the system kept supplying power during an outage, electricity would flow back into the lines that utility workers are repairing, which could kill them. It is not an equipment fault but a mandatory requirement.
Off-grid: for places the grid doesn't reach
A system with no connection to the utility at all, producing its own power and storing all of it in batteries. It suits places the grid genuinely does not reach, such as a hut in the middle of a plantation, a raft house on a lake, or an island with no electricity supply.
Be aware that an off-grid system has to be designed for several consecutive days of rain, which happens often in the South. That means much larger battery capacity than you might expect, and far higher cost than on-grid.
If your land already has grid power, there is almost no economic case for choosing off-grid.
Hybrid: the middle ground
Connected to the grid like on-grid, but with batteries to store power as well. During a power cut the system switches to supplying the designated circuits from the battery.
It suits areas with frequent power cuts, or homes with equipment that must not stop, such as home medical equipment, medicine refrigerators, or systems used in aquaculture.
It costs considerably more than on-grid, because you need both batteries and a different type of inverter, and batteries have a limited lifespan, so you need to budget for replacing them in the future.
So which should you choose?
- If your home is in an area where power cuts are rare and your goal is a lower bill, choose on-grid — it gives the best value and is the easiest to maintain.
- If power cuts are frequent enough to affect your life or business, consider hybrid — but work out separately whether the battery pays for itself.
- Only choose off-grid if the grid genuinely does not reach you.
The advice we always give is: don't buy a battery because you are worried about one or two power cuts a year. Putting that money into more panels brings a bigger return.
Frequently asked questions
Can I install on-grid now and add a battery later?
Yes, if it is planned from the start by choosing an inverter that supports adding a battery. If a standard on-grid inverter is already installed, adding a battery later usually means replacing the inverter and discarding the old one — so mention this intention at the design stage.
How long do batteries last?
It depends on the type and how it is cycled. The lithium batteries used today usually state a cycle count in their specifications, which translates into roughly ten years of typical use. It is sensible to budget for one battery replacement over the life of the system.
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Keep reading
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