Commercial solar in 2026: the new 100 kW to 1 MW rules, and choosing an installer

Three size bands

What changes for mid-scale solar from 1 October 2026?

From 1 October 2026, systems over 100 kW and up to 1 MW have their own mid-scale path:

• Eligible: systems over 100 kW and up to 1 MW installed from 1 October 2026. “Installed” means first able to produce electricity, which is the commissioning date on the electrical compliance certificate.
• Up-front certificates: STCs for 5 years of deemed output, fixed at that length each year to 2030. Small systems, by contrast, lose a year of deeming every January (5 years in 2026).
• Or ongoing certificates: you can choose REGO certificates under the Guarantee of Origin scheme instead. If you take STCs, you can't also create REGO certificates for the deeming period.
• Evidence: planning and network connection approvals, engineering reports and a written installer statement, with approved components and an SAA-accredited installer.
• The 1 MW cap counts related systems: adjacent or related systems on the same site, including existing ones, count towards it. Extending an existing system earns STCs on the new capacity only.
• Timing: applications open in mid to late November 2026; systems installed from 1 October are assessed under the rules at that date.

These are our estimates using the regulator's zone ratings. The Clean Energy Regulator's calculator gives the exact entitlement. Note the effect of the fixed deeming period: from 2027, a mid-scale system is credited for more years of output than a small one.

How does a larger system get connected to the grid?

Larger systems need your network's approval before they're built. Under the national connection guidelines, basic connections go up to 30 kVA three-phase, with exports usually limited to around 5 kVA per phase. Above that, the network sets export limits case by case, you pay for any technical studies, and an engineer signs off commissioning. Allow time and budget for this, and get the network's requirements in writing early, including any change to your tariff.

What size commercial solar system do you need?

Size business solar to your load, not your roof: it pays back fastest when you use most of what it produces. Your electricity interval data (the half-hourly readings from your meter, often called NEM12) shows when you use power and what your demand charges are. A good installer designs from that data, not from a single bill. Batteries can also reduce demand charges, and NSW has business battery incentives (BESS4 and BESS5) that stack with the federal discount. Our business assessment starts from your data.

How do you choose a commercial solar installer?

When you choose a commercial solar installer, check:

• SAA accreditation, current electrical licences, and a track record on systems of similar size (ask for references you can call)
• Who does the work: in-house teams or subcontractors
• A design based on your interval data, with expected generation, self-consumption and savings, and the assumptions behind them
• Network approval handled and costed up front, plus building and structural approvals where needed
• Performance guarantees, monitoring (who watches it, and what happens when output drops), and a written maintenance agreement
• Product and workmanship warranties, handover documents, an operations manual and training for your staff

Buy it, or sign a power purchase agreement?

With a power purchase agreement (PPA), a provider installs and owns the system and you buy its electricity at an agreed rate, usually over 10 to 15 years. No capital outlay, but often more expensive overall than buying. Check how the rate rises each year, who gets the export credits, whether you pay for all generation or only what you use, who maintains the system, and what it costs to exit early or if you sell the building.