The guide
What a commercial system is, how it gets sized, what it costs and what actually changes the answer. Written for the person who has to justify the spend.
The short answer
A commercial solar system is a rooftop or ground-mounted array sized against a business’s own electricity consumption rather than its roof area. Australian commercial systems typically run from 30 kW to 1 MW, use larger-format panels of 550 to 700 W, and connect through a three-phase inverter with network approval.
Indicative installed cost runs roughly $900 to $1,300 per kW before the STC discount, with most well-matched sites landing on a payback between three and six years. The figure that moves it most is not the price per kW — it is how much of the generation the site uses itself. See the full cost breakdown.
Installed from
1 Oct
2026
Regulations made on 16 September 2026 extend the STC discount from systems up to 100 kW to systems up to 1 MW, for solar installed from 1 October 2026. The Clean Energy Regulator says applications will not open until mid to late November 2026.
Sources: Mid-scale Solar Regulations 2026 (Federal Register of Legislation) (opens in a new tab); Clean Energy Regulator: mid-scale solar (opens in a new tab)
Equipment
The physics is the same. Almost everything else is different, and the differences are what make a residential quote a poor guide to a commercial one.
The core of it
The most common mistake in a commercial solar quote is sizing to the available roof area and then working out what it saves. That gets the order backwards, and it is the reason payback figures on comparable buildings vary so widely.
The three things that decide a system’s worth, in order:
A bill carries all three. That is the entire reason this service asks for one rather than for a floor area and a postcode.
Send your billAfter the array
Two questions that come after the sizing, not before it.
Storage
A battery is a second decision, not part of the first. Most commercial sites should size solar against their daytime load first and look at storage afterwards, because the case for storage usually rests on demand charges rather than on storing cheap energy.
Where it does stack up: a site with a sharp, predictable peak that falls outside daylight, or one in New South Wales where the Peak Demand Reduction Scheme pays for capacity that can be dispatched at the right time.
Getting it built
The network application is the one that sets the calendar, and it can run from a few weeks to several months depending on the distributor and the system size.
Each stage, realistic timings, and choosing an installerBy site type
Refrigeration is the best load profile in commercial solar: it runs through the day, it runs in summer when generation peaks, and it is rarely switched off. Large uninterrupted roofs help, though the limit is usually the switchboard rather than the area.
Three-phase plant, high consumption and demand charges that often dominate the bill. Shift patterns decide everything: a single day shift is an excellent fit, a 24-hour operation less so unless storage is part of the answer.
Irrigation pumps, dairy sheds and packing lines, often at the end of a long rural feeder where the distributor limits or prohibits export. Systems here are sized tightly to on-site use, and the export limit needs confirming before anything is designed.
Daytime-only load with a good match to generation, undone somewhat by weekends and long holidays when the site is empty and everything is exported. Sizing to term-time load rather than to annual consumption is usually the better answer.
Not one of these? The sizing exercise is the same either way. Send your bill and we’ll tell you what your load actually supports.
Where we work
Export limits, connection thresholds and what a panel actually generates all move between states. Each page covers the local detail.
ACT
Capital Territory
QLD
Queensland
VIC
Victoria
SA
South Australia
WA
Western Australia
We quote Australia-wide. Not listed? Send your bill anyway.
Questions
It depends on the daytime load, not the roof. A site drawing 200 kWh through the working day suits something very different to a site with the same annual bill concentrated in an evening peak. Most Australian commercial systems land between 30 kW and 1 MW, and the sizing exercise is a load profile against a generation profile, which is why a bill is more useful than a floor plan.
Commercial installs usually run larger-format panels, roughly 2.2 to 2.4 metres long, at higher wattages, typically 550 W to 700 W each. Fewer panels, fewer connections and less labour for the same capacity. The inverters are three-phase, and above a certain size the system needs network approval rather than a simple connection notice.
Usually not on exports alone. Feed-in rates for commercial sites are low and midday wholesale prices in some states sit near zero, so a system earns its money by covering power you would otherwise buy. A site that uses most of its power overnight gets a much weaker result than one running plant through the day, and any proposal that leans on export revenue to make the payback look good is worth checking carefully.
The install itself is usually days to a few weeks depending on size. The timeline is dominated by network approval, which can run from a few weeks to several months for larger systems, and by equipment lead times. Anyone quoting a firm completion date before the network application is lodged is guessing.
If it's installed from 1 October 2026 and it's no bigger than 1 MW, yes. The Mid-scale Solar Regulations 2026 were made on 16 September 2026 and extend the STC discount from systems up to 100 kW to systems up to 1 MW. The 1 MW limit counts any solar already on the site. Applications will not open until mid to late November 2026, so ask how a quote handles the gap between switch-on and the certificates being processed.
Last updated 18 September 2026.
One recent bill is enough to turn everything on this page into numbers for your site.
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