Commercial solar calculator
See how much solar your business roof can hold, what it would generate each month and what it could save. Enter the site address to check its region and rebate. No name or email needed.
Monthly generation
- Used on site
- Exported
- Your average monthly use
Confirm your address to see monthly generation.
Get a detailed assessment for your site
The estimate above runs on assumptions. Send your details, and a recent bill if you have one, and we will prepare an assessment from your real data.
- A priced design, with the investment and payback worked out from your real data
- The roof: sections, orientation and shade
- Your tariff, usage and demand charges, reviewed by our team from the bill
- How a battery stacks up against your load profile, and the system size that suits it
- The network's export rules and the certificates the system would create
Commercial solar sizing questions
How much solar does my business need?
Enough to cover the electricity the site uses while the sun is up. The calculator’s “Suits your use” option sizes the system so its assumed on-site share fits within average usage in every month, subject to the roof limit. Interval data from your meter shows the daylight load, and a detailed assessment checks the size.
How many solar panels fit on a commercial roof?
Once roof edges, walkways, plant and skylights are allowed for, the calculator assumes 50 to 70% of a commercial roof is usable (60% to start), at about one panel for every 2.3 m² of usable roof. On those assumptions a 1,500 m² roof fits about 388 panels, or 197 kWp.
How much can commercial solar save?
It depends on your energy charge and how much of the solar the site uses. In Brisbane, each kWp of panels laid flat generates about 1,385 kWh a year. At 27 c/kWh with 80% used on site, that saves about $299 a year per kWp, excluding GST. This is an illustrative model, not a guaranteed saving. Solar doesn’t reduce daily supply charges.
What rebates apply to commercial solar?
The federal incentive is small-scale technology certificates (STCs), usually taken as an upfront discount. Systems above 100 kW and up to 1 MW installed from 1 October 2026 can create them too (mid-scale solar certificates). The number depends on system size and your postcode’s zone. This estimate uses a five-year deeming period for installation in 2026. Systems above 1 MW use a different scheme.
Does a battery make sense with commercial solar?
A battery stores midday solar for the evening and can lower demand charges when it discharges at the site’s peak. Whether it pays depends on your load profile and tariff. Send us a bill or interval data and we’ll show how a battery stacks up for your site.
This is an estimate, not a quote or design. It uses PVGIS 5.3 yield profiles for unshaded, flat panels with 14% system losses at the nearest modelled city. The address selects a regional weather profile; it does not scan, measure or assess your roof. Capacity assumes 0.22 kWp per usable square metre, rounded down to whole panels.
Annual electricity use is spread evenly over 12 months. The on-site share is your assumption and is capped by each month’s usage; interval meter data is needed to assess coincidence with generation. Savings model first-year energy charges and export credits excluding GST, daily and demand charges, shade, network export limits, battery operation, finance, maintenance, degradation and recurring certificate income. Initial rates and usage are illustrative, not a tariff offer. Change them to match your contract and bill. The initial annual use of 100,000 kWh and usage rate of $0.27/kWh are illustrative.
The indicative upfront STC amount uses the verified address postcode’s official zone rating, whole-system capacity and the installation year. Certificate counts are rounded down. Small-scale deeming runs to 2030; eligible mid-scale systems use a fixed five-year period. For 2026 mid-scale installations, the model assumes installation on or after 1 October. This estimate fixes installation in 2026 and uses the historical $39.85 spot price reported by the CER on 14 August 2026, not a live quote. The amount excludes GST; fees, eligibility, assignment and payment terms may change the amount you receive. CER entitlement rules and mid-scale application guidance.