Commercial solar in Melbourne
How business solar differs from residential solar, what makes a site suitable and the numbers that matter before requesting proposals.
Read guide ↗Commercial solar in Melbourne: from 30 kW to 1 MW.
Commercial solar is a load, roof, electrical and network project before it is a panel purchase. The strongest business case starts with measured interval data and makes every major assumption visible.
Last updated: 5 October 2026. Incentive information on this page reflects rules current on that date.
What should a business know first?
For most businesses, the most valuable solar electricity is the electricity used on site while it is being generated. That means system sizing should begin with when the business consumes electricity, not with how many panels can fit on the roof.
A good commercial proposal should use at least 12 months of interval consumption data where available. It should show how much proposed generation is expected to be self-consumed, how much is exported, what import and export tariffs are assumed, and whether demand charges are likely to change.
IMPORTANT 2026 INCENTIVE CHANGE
Eligible solar systems above 100 kW and up to 1 MW installed from 1 October 2026 can now use the expanded federal Small-scale Renewable Energy Scheme and create STCs under the mid-scale solar rules. Victorian commercial projects from 30 kW to 200 kW may also qualify for the Victorian Energy Upgrades solar activity. Do not assume two incentives can automatically be combined. Confirm the treatment of the actual project before signing.
Commercial solar sizing starts with interval data
A quarterly bill shows how much energy the business bought. Interval data shows when the business bought it. That distinction drives commercial solar economics.
A site drawing 80 kW steadily through business hours may absorb a large solar array very efficiently. Another site with the same monthly consumption but most of its load after sunset may export much more solar and receive a lower value for each extra kilowatt installed.
Model several system sizes against the same interval dataset. Compare self-consumption, exports, annual generation and project cost rather than selecting a standard 30 kW, 50 kW or 100 kW package without reference to the load profile.
Roof area is only one design constraint
Large commercial roofs can be excellent solar assets, but usable roof area can be reduced by skylights, plant, vents, access paths, shade, fire-safety requirements and structural limits.
Older warehouses and factories may need structural engineering or roof remediation before the final array is fixed. The electrical side also matters: incoming supply, three-phase configuration, switchboard capacity, protection equipment, cable routes and the location of inverters or batteries can materially change the project scope.
A business should not assume that a three-phase supply automatically allows any inverter size. The distributor's connection offer and the site's electrical infrastructure still control the practical design.
Demand charges can change the ROI calculation
Some commercial electricity tariffs include demand charges based on the highest measured demand during a defined period. Solar may reduce those charges when the site's demand peak overlaps with solar production, but it may have little effect if the peak occurs after sunset or during a short process-load event.
A credible savings model should therefore separate energy-charge savings from any demand-charge savings. It should not simply multiply all solar generation by a retail electricity rate.
Network connection becomes more important as systems get larger
The distribution network needs to assess the proposed generator against the local network and the site's existing connection. Larger projects can require more detailed connection studies, protection design, export control and switchboard work.
An export limit does not necessarily make a large system uneconomic. A business with strong daytime demand may consume most generation behind the meter. But the export offer should be known early enough that it can be included in the financial model rather than discovered after the system size has been selected.
Current Victorian and federal incentives
Victoria's standard Commercial and Industrial Solar activity under the Victorian Energy Upgrades program covers qualifying non-residential solar systems from 30 kW to 200 kW. The discount is certificate-based and the dollar value can move with VEEC prices.
Federally, eligible solar systems up to 100 kW continue to use the normal SRES/STC pathway. From 1 October 2026, eligible systems above 100 kW and up to 1 MW can also create STCs under the new mid-scale solar rules, using a fixed five-year deeming period through 2030.
Projects above 200 kW sit outside Victoria's standard 30 to 200 kW solar activity, although other VEU project-based pathways may be relevant. Federal mid-scale SRES eligibility can still extend to 1 MW. Certificate choices and interactions should be confirmed for the specific project rather than inferred from a residential quote template.
Commercial batteries need a defined job
A commercial battery can shift solar into later hours, reduce some demand peaks, support selected critical loads and absorb generation that would otherwise be curtailed. Those are different jobs and they can require different combinations of battery capacity in kWh and power in kW.
Do not add a battery to a commercial proposal simply because storage is available. Model what it is expected to do, how often it will cycle, the tariff value it is targeting, and the power required for demand management or backup.
Plan for EV fleets and future electrification
Future electric forklifts, fleet charging, refrigeration, process heat, heat pumps, new production equipment and longer operating hours can increase daytime electricity demand. Those loads can strengthen the case for a larger array if they are likely to materialise.
The opposite also matters. If a business is planning to downsize, automate, relocate or reduce operating hours, sizing purely from last year's interval data can overstate future solar value.
How should commercial solar ROI be calculated?
There is no responsible universal payback period for Melbourne businesses. A project should model at least the installed cost after separately identified incentives, expected solar generation, self-consumption, export value, tariff escalation assumptions, degradation, operating and maintenance costs, and any demand-charge effect that can be supported by the load data.
Where finance, tax depreciation or accounting treatment materially affects the decision, those assumptions should be handled with the business's accountant or finance adviser rather than presented as a generic solar saving.
Commercial solar guides
Commercial solar rebates and incentives
VEU support, federal STCs, the 100 kW to 1 MW mid-scale rules and where other certificate pathways may apply.
Read guide ↗30 kW, 50 kW, 100 kW or 200 kW?
A practical guide to sizing around interval data, roof area, export constraints and future electrification.
Read guide ↗Commercial solar payback and ROI
How to model avoided imports, demand charges, export value, degradation and realistic project returns.
Read guide ↗Solar for warehouses and factories
Structural capacity, switchboards, operating hours and process loads can matter as much as the size of the roof.
Read guide ↗Commercial solar grid connection in Victoria
Why larger systems need network assessment, what export constraints mean and why connection work belongs early in the project.
Read guide ↗Commercial batteries
When storage can help with demand management, solar shifting, resilience and tariff optimisation, and when it simply adds cost.
Read guide ↗What Melbourne Solar Guide does
Melbourne Solar Guide is an educational buyer resource. These pages explain the questions to ask and the assumptions worth challenging. Final structural engineering, electrical design, protection, network connection, incentive eligibility, tax treatment and project finance must be confirmed for the actual site by appropriately qualified parties.