100 kW
$100,000–$140,000
Factory, cold store, large warehouse
Reviewed 8 September 2026 · Australian commercial projects, 100 kW and up
Buying commercial solar panels: the 2026 guide for Australian businesses
Written for bigger commercial sites. How to size a system from your interval data, what $100k-to-$1M-class projects should cost in 2026, how the STC expansion, feed-in tariffs and export approvals change the maths, and what to check before you sign.
Sizing
Start with the load, not the panels.
Solar only saves real money when generation lands on top of daytime usage. Interval data shows where that happens on your site; the ÷4 rule turns it into a first estimate.
What is interval data?
The 30-minute usage record held by your meter. It shows the shape of your day — the difference between a café that sells coffee at 7am and a cold store that runs flat out from 10am. No interval data means every quote is a guess; download 12 months from your retailer before taking any meeting. (You can run a free site snapshot with it too.)
The ÷4 rule for NSW
NSW sites average about 4 peak sun hours a day — more in summer, less in winter — so each kW of solar produces roughly 4 kWh/day. Divide your average daily kWh by 4 for the system size that would cover it: a site using 2,000 kWh/day maps to ~500 kW. Then be honest: exports earn cents, not dollars, so size to your daytime usage instead. Covering the evening peak is a battery question, not a solar one — and on most tariffs the evening peak also drives your demand charges.
Cost
What a commercial solar system should cost.
Indicative installed bands before incentives. The roof type, switchboard work and monitoring choice move any quote within — or past — its band.
250 kW
$225,000–$325,000
Distribution centre, manufacturing line
500 kW
$425,000–$625,000
Multi-roof industrial, agribusiness
1 MW
$800,000–$1,150,000
Large distribution hub, processing plant
Above 1 MW
LGC territory
Generation-scale: engineering-led pricing, PPA options
The STC cap is lifting to 1 MW. On 5 August 2026 the Australian Government announced STC eligibility for solar PV will expand from 100 kW to 1000 kW (1 MW), expected 1 October 2026, subject to the required regulations being made. Systems between 100 kW and 1 MW — previously large-scale generation certificate (LGC) territory — would earn STCs as an upfront discount instead. Quote the timing both ways until the regulations land.
Rule of thumb: payback = net cost ÷ first-year bill savings. Good self-consumption sites see 3–5 years. A quote without a yield estimate and payback model is not a quote.
Approvals
Solar feed-in tariffs in NSW, and getting connected.
The business case should stand up on self-consumption alone. Feed-in tariffs are a bonus, and export approval is a process — plan both.
Feed-in tariffs are small now
IPART’s NSW benchmark for 2026–27 is 3.4–6.5 c/kWh all-day, down from 4.8–7.3 c/kWh. No minimum is regulated and some plans pay nothing. Power you use on site saves the ~30c retail rate; power you export earns cents. See the full current register on incentives.
Export limits and approval
Basic connections allow roughly 10 kW export per phase. Above ~30 kW the distributor sets a bespoke export limit — which can be low or zero on constrained network sections. Ausgrid does not guarantee export for larger systems, and export-limiting hardware can be a condition of approval. Model the two-way tariff before accepting it.
Plain English
Panels, batteries, inverters — what each one actually is.
Every commercial quote is three pieces of equipment and two units that get confused constantly. Here is the whole system in plain English.
What is a solar panel?
A panel is a maker of electricity, rated in watts — and watts are a rate, like litres per hour. A modern commercial module is around 650 W: in full sun it produces about 650 Wh every hour, and across a NSW day that averages out to roughly 2.6 kWh. Put seven or eight hundred of them on a warehouse roof and you have a ~500 kW array making about 2 MWh on a good day.
What is an inverter?
Panels make direct current (DC); your equipment and the grid run on alternating current (AC). The inverter converts one to the other and syncs the whole array to the grid. It is usually sized smaller than the panel array — around 1.2–1.3 panels-to-inverter — because peak sun is brief, and a little clipped peak is cheaper than a bigger inverter. This is why "a 500 kW system" needs stating twice: 500 kW of panels, perhaps 400 kW of inverter. A quote that doesn’t separate the two isn’t finished.
What is a battery?
Two ratings, easily confused. kWh is capacity — the fuel tank, how much evening you can carry. kW is power — the engine, how much it can deliver at once. A 50 kW / 100 kWh battery runs flat out for two hours, or trims a longer, lower evening peak. Match the tank to the hours you need to cover and the engine to your peak demand; and if a battery is in the quote, check whether it actually pays on your tariff.
How the three fit together
The array (panels) makes DC power through the day. The inverter turns it into AC for your equipment, and the battery sits on the AC side soaking up anything you can’t use, for the evening peak. Size each against your interval data: panels to daytime load, inverter to the array, battery kW to peak demand and kWh to the hours after sunset.
Selection
Choosing a commercial solar installer.
The quote is only half the product; the other half is who answers the phone in year seven.
What separates a good one
- Clean Energy Council accreditation, in-house or named crews
- A yield guarantee, not just a performance-warranty PDF
- Monitoring included, with alerting someone actually watches
- Switchgear contingency priced up front, not as a surprise
- Commercial references at sites like yours
Red flags
- Priced per panel with no load analysis
- "Fill the roof" sizing on an interval-data-free basis
- Pressure toward a locked-in PPA before your numbers are known
- Warranties held by an entity one director change from gone
Comparing commercial solar companies? Ask each for the same three references and the same assumptions — that makes them comparable.
Before you sign
The five-point commercial solar checklist.
- 01
12 months of interval data
Your meter records usage every 30 minutes. It shows when you use power, not just how much — the difference between a system sized to your business and a system sized to your roof. Your installer can download it with your NMI and a signed authority.
- 02
A structural check of the roof
Before hundreds of kW of panels goes up, an engineer confirms the structure carries roughly 10–15 kg per m² of covered roof plus wind uplift for your terrain. The certificate is what your certifier and insurer will ask for. Price any roof repairs before quotes, not after.
- 03
Switchboard and supply headroom
The solar breaker needs a spare way on a serviceable switchboard, and a 100 kW inverter draws about 160 A per phase at 400 V. Older boards and tight supplies are a common hidden cost — confirm both early.
- 04
A connection application path
Your installer lodges an application with the distributor (Ausgrid, Endeavour or Essential in NSW). Above roughly 30 kW expect a bespoke export limit, which can be low or zero on constrained parts of the network. Allow weeks, not days.
Read the NSW distributor tariff guides - 05
Three quotes on identical assumptions
Same tariff, same escalation, same degradation, same export limits — or the comparison is meaningless. A per-kW price without a yield estimate is not a price.
Get a sized assessment, not a per-panel price.
Check the roof, connection, load shape and tariff first — then let the interval data size the system.
Scope: grid-connected commercial solar on NSW and Australian business premises. Cost bands are indicative 2026 installed prices before incentives and vary with roof type, switchboard condition and export limits. This guide is general information, not financial or engineering advice; confirm tariffs and connection conditions with your distributor and retailer before committing.