Commercial Solar Systems in Australia: The Complete 2026 Guide

The daily output figures are averages based on a typical Australian location with good sun exposure. Actual output varies with location, orientation, shading, and time of year. Systems under 100kW are classified as small-scale under the Renewable Energy Target and qualify for STC rebates. Systems above 100kW are large-scale and create LGCs (Large-scale Generation Certificates) instead, which work differently.

If you run a farm, we have a dedicated farm solar guide that covers ground-mount arrays, irrigation pumps, and the specific economics of agricultural solar.

These are ballpark ranges. Your actual quote will depend on the panel and inverter brands you choose, how complex your roof is (tin is cheaper than tile, single-storey is cheaper than multi), whether you need electrical switchboard upgrades, and whether you are in a metro or regional area. For a more detailed pricing breakdown, see our commercial solar cost guide.

Most commercial premises have three-phase power, which is actually an advantage for solar. Three-phase connections allow larger inverters and more balanced power distribution across the building. Residential homes are typically single-phase, which limits inverter size to around 5kW per phase.

With three-phase, you can install a single large three-phase inverter (common for systems 15kW to 100kW) or multiple smaller inverters spread across phases. Your installer will recommend the best configuration based on your switchboard, load profile, and any network export limits.

If your premises currently has single-phase power and you want a system larger than about 5kW, you may need to upgrade to three-phase. This involves your electricity distributor and can cost $2,000 to $6,000 depending on the distance from the street transformer. Your installer can assess this during the site visit.

The payback period for commercial solar is typically shorter than residential because businesses consume a higher proportion of their solar generation on site. A cafe open from 7am to 3pm will use almost everything its panels produce. A warehouse running machinery during business hours will do the same.

For a business paying 30 to 40 cents per kWh on a commercial tariff and self-consuming 70% or more of their solar generation, payback is typically 3 to 4 years. Businesses on cheaper tariffs or with lower self-consumption rates (such as those that close on weekends) may see payback in 4 to 6 years.

After the payback period, the system continues generating for another 20+ years. That is 20 years of near-zero electricity cost during daylight hours. For a 30kW system saving $8,000 per year, the total lifetime savings come to roughly $160,000 to $200,000 on a $27,000 investment.

Tax benefits accelerate the payback even further. The instant asset write-off lets qualifying businesses deduct the full system cost upfront, and state commercial solar rebates can reduce the out-of-pocket cost by thousands more.

For businesses above the write-off threshold, solar panel depreciation through the ATO's general or simplified depreciation rules still delivers significant tax savings over time.

Not every solar installer does commercial work. Commercial installations require different skills, equipment, and accreditation compared to residential jobs. When vetting commercial installers, look for:

Most small and medium businesses buy their solar system outright. It gives the best long-term return because you own the asset, claim the depreciation, and keep all the savings. But there are alternatives if upfront capital is a constraint.

A chattel mortgage is the most popular financing option. You own the system from day one (so you claim the instant asset write-off and depreciation), and the repayments are often less than the electricity savings, making the system cash-flow positive immediately.

Power Purchase Agreements (PPAs) are more common for large systems (50kW+). A third party installs and owns the system on your roof, and you buy the electricity it produces at a fixed rate, typically 20 to 40% below grid rates. There is no upfront cost, but you give up ownership and the long-term savings are lower than buying outright.

After working with hundreds of commercial solar installations, these are the issues that trip businesses up most often.

Oversizing for export. A system designed to export lots of power back to the grid sounds great in theory. In practice, commercial feed-in tariff rates are often 3 to 7 cents per kWh, which barely moves the needle on ROI. Size for self-consumption first.

Ignoring the roof. Old or damaged roofing needs to be repaired before panels go on top. Once panels are installed, accessing the roof for repairs becomes expensive. Get a roof condition report before committing to solar.

Not checking the lease. If you are renting, your landlord needs to approve the installation. Some leases have clauses about alterations to the building. For longer-term leases, the landlord may agree because solar adds value to their property, but get it in writing.

Comparing quotes on price alone. A $25,000 quote with budget panels and a 5-year workmanship warranty is not the same value as a $30,000 quote with Tier 1 panels and a 10-year workmanship warranty. Look at the total cost of ownership, including expected degradation, warranty terms, and monitoring. Our panel selection guide explains what matters.