On-grid solar systems in South Australia are the default choice for a reason. They are the simplest configuration, the cheapest to install, and in a state with expensive retail electricity and abundant sunshine they start reducing bills from the first clear day. This guide covers how they work, what shapes the price, what the grid connection involves here, and where their limits are.
What an on-grid solar system is
An on-grid, or grid-connected, system is wired into the local electricity network and has no battery. Your home runs on solar while the sun is up, surplus generation is exported to the grid, and anything you need beyond what the panels produce is drawn from the grid as usual.
It differs from the two other configurations in one respect each:
- Off-grid has no network connection at all and depends entirely on panels and a large battery bank. It is a niche solution for properties the network does not reach.
- Hybrid keeps the grid connection but adds storage, so evening load is covered by your own daytime surplus.
How on-grid solar works through a South Australian day
The panels generate DC electricity. An inverter converts it to the AC your home uses. From there the order of priority is fixed: your current household load is served first, and only the leftover is exported.
That order is why self-consumption matters more than total generation. A kilowatt-hour you use yourself is worth the full retail rate you would otherwise have paid. A kilowatt-hour you export is worth your retailer’s feed-in rate, which in South Australia is now a small fraction of the buy-back price. We cover the current picture in our SA feed-in tariff guide.
The practical consequence is simple. Shifting the dishwasher, pool pump, hot water and laundry into the middle of the day is free money on an on-grid system, and it is the first thing we suggest to anyone whose bill has not dropped as much as they expected.
Why on-grid suits South Australia
- Strong sunshine. Adelaide gets among the highest solar irradiation of any Australian capital, so a given array produces more here than in most of the country.
- Expensive grid power. South Australian retail rates are among the highest nationally, which raises the value of every unit you generate and use.
- Federal support. The Small-scale Renewable Energy Scheme reduces the upfront cost through STCs, applied as a discount in your quote rather than a payment later.
- No battery to maintain. Fewer components means a lower entry price and less to go wrong.
Choosing a system size
Size should follow your usage and your roof, not a round number in an advertisement.
| System size | Typically suits |
|---|---|
| 5kW | Smaller households, units, limited roof space |
| 6.6kW | The most common choice for an Adelaide family home |
| 10kW | Larger homes, ducted air conditioning, pool, or an EV |
| 20kW and above | Businesses, workshops and commercial premises |
A 6.6kW system remains the sensible default for most households because it pairs with a common inverter size and fits the majority of Adelaide roofs. If your consumption is heavier, or an electric vehicle is on the horizon, going larger at installation is far cheaper than extending later. Our solar sizing guide for SA works through this properly, and commercial solar is sized on a different basis again.
The components that matter
Panels
Nearly all residential panels sold in Australia now are monocrystalline. What separates them is the manufacturer’s warranty terms, the degradation rate over 25 years, and whether the company will still exist to honour a claim. Ask for the performance warranty, not just the product warranty.
Inverter
This is the component most likely to need attention first, and the one most worth spending on. String inverters suit simple unshaded roofs. Micro-inverters or optimisers make sense where shading or multiple roof orientations are involved. A hybrid inverter costs more but leaves the door open to adding battery storage without replacing equipment.
Switchboard and metering
Older switchboards often need upgrading before a system can be connected safely. This is the single most common source of surprise costs, and it is also the easiest thing for an installer to check before quoting rather than after. Your retailer will also need to reconfigure or replace the meter so exports are recorded.
What drives the price
We quote per home after a site visit rather than publishing a figure, because the same system size can vary considerably depending on what the installer finds. The variables that move a price are:
- Panel and inverter brand, and the warranty terms behind them
- Roof type, pitch and height, and whether the work needs edge protection or scaffolding
- Number of roof planes and orientations, which affects racking and string design
- Switchboard condition and whether an upgrade is required
- Cable run length from the array to the inverter and switchboard
- Whether you are specifying a hybrid inverter for future storage
STC value is deducted from the installed price, so the figure you are quoted should already include it. Ask for that line to be shown separately so you can see what you are actually paying.
Grid connection and export limits in SA
South Australia has one of the highest concentrations of rooftop solar anywhere, and the network manages that by controlling how much can be exported at times of very high generation. New systems must be remotely controllable so exports can be curtailed when the grid needs it.
Your installer applies for the connection approval and handles the paperwork. What you should ask is what export limit applies to your address and how it is expected to affect you, because on a saturated feeder it can be the difference between a system that performs as modelled and one that does not.
What on-grid solar cannot do
- Keep your power on in a blackout. A grid-connected system shuts down during an outage so it cannot energise lines crews may be working on. Backup needs a battery and a dedicated essential-loads circuit.
- Cover your evening peak. Generation stops at sunset, which is usually when household consumption is highest.
- Earn much from exports. Feed-in rates have fallen steadily. Building your expectations around export income will disappoint you.
None of these are reasons to avoid on-grid solar. They are reasons to size it around daytime self-consumption and to specify a hybrid inverter if storage is a possibility later. Our guide to panels versus batteries covers that decision.
Installation, start to finish
- Site assessment. Roof space, pitch, orientation, shading across the year, switchboard condition and meter type.
- System design and quote. Panel layout, string design, inverter selection, and a fixed written price.
- Grid pre-approval. Submitted by the installer before anything goes on the roof.
- Installation. Racking, panels, DC and AC wiring, inverter mounting, isolators and any switchboard work. Typically one day for a standard residential system.
- Testing and certification. Commissioning, a certificate of electrical safety, and the compliance paperwork for the STC claim.
- Meter reconfiguration and handover. Your retailer updates the meter, and you are shown the monitoring.
Maintenance
On-grid solar is low maintenance rather than no maintenance. Check the monitoring occasionally so a fault does not go unnoticed for months, watch for inverter error codes, and keep the panels reasonably clean. Adelaide’s dry summers and pollen mean most roofs benefit from a wash once or twice a year. Our guide to cleaning solar panels in South Australia covers doing it safely and when not to attempt it yourself.
Frequently asked questions
What is an on-grid solar system?
A solar system connected to the electricity network with no battery. It powers your home during the day, exports the surplus, and draws from the grid when the panels are not producing enough.
Does on-grid solar work during a blackout?
No. The system disconnects automatically for the safety of anyone working on the network. Backup power requires storage and a correctly configured essential-loads circuit.
How many panels are in a 6.6kW system?
Usually around 15 to 17 panels, depending on the wattage of the panel used. Higher-output panels mean fewer of them and less roof area.
How long does an on-grid system last?
Panels are generally warranted for performance over 25 years. Inverters are the shorter-lived component and are commonly replaced once over the life of the system.
Can I add a battery to an on-grid system later?
Yes, and it is far simpler if the system was specified as battery-ready with a hybrid inverter. Otherwise storage can still be AC-coupled alongside your existing inverter.
Do I need council approval?
Standard rooftop solar on a residential property generally does not. Heritage listings, strata arrangements and some commercial premises are the exceptions, so check if any of those apply to you.
Get an on-grid system sized for your roof
We are SAA-accredited, licensed South Australian electricians based in Salisbury North, working across greater Adelaide. We assess the roof and the switchboard before quoting, handle the grid approval and the STC paperwork, and give you a fixed written price within 48 hours of the site visit.
Book a free site assessment, or call 0403 754 245.
