Australian businesses considering commercial solar face three distinct government incentive schemes: Small-scale Technology Certificates (STCs), Victorian Energy Efficiency Certificates (VEECs), and Large-scale Generation Certificates (LGCs). Each operates under different rules, covers different system sizes, and delivers value in fundamentally different ways. STCs provide a one-time upfront discount on systems up to 100 kW. VEECs add a Victoria-only bonus for systems between 30 and 200 kW. LGCs generate ongoing annual revenue for systems above 100 kW.
Understanding which schemes apply to your business, and whether they stack, is not academic. The difference between capturing all eligible incentives and missing one can shift a commercial solar payback period from three years to six. This guide breaks down each scheme with real numbers, worked examples, and the stacking rules you need to model accurately.
Quick comparison
| Scheme | Scope | System size | Type | Typical value (50 kW) |
|---|---|---|---|---|
| STC | Federal (all states) | Up to 100 kW | One-time upfront | $10,000–$15,000 |
| VEEC | Victoria only | 30–200 kW | One-time upfront | $4,000–$5,000 |
| LGC | Federal (all states) | Above 100 kW | Annual recurring | N/A (starts at 100+ kW) |
STCs: the federal upfront discount
Small-scale Technology Certificates are the backbone of Australian solar incentives for systems up to 100 kW. Administered by the Clean Energy Regulator under the federal Renewable Energy Target, STCs represent the expected generation of a solar system over its remaining deeming period, which runs until 2030. In 2026, that means four years of deemed generation credited upfront at the point of installation.
The number of certificates your system earns depends on three factors: system capacity in kilowatts, the STC zone multiplier for your location, and the remaining deeming period. Australia is divided into four STC zones based on solar irradiance. Zone 1 (far north Queensland, Northern Territory) carries the highest multiplier at 1.622. Zone 2 covers inland NSW and parts of central Australia at 1.536. Zone 3, which includes Sydney, Brisbane, Perth, and Adelaide, uses 1.382. Zone 4 (Melbourne, Hobart, and southern coastal areas) sits at 1.185.
Worked example: A 50 kW system installed in Sydney (Zone 3) in 2026 generates 50 × 1.382 × 4 = 276 STCs. At the current spot price of approximately $39 per certificate, that equates to roughly $10,770 as an upfront discount on the installation cost. Your installer typically handles the STC assignment and applies the discount directly to your invoice.
The deeming period decreases by one year annually, so systems installed in 2027 receive three years of deeming, 2028 receives two, and so on. Every year you delay reduces the STC value by approximately 25%. See the full NSW incentive breakdown.
VEECs: Victoria's additional state incentive
Victorian Energy Efficiency Certificates are a state-level incentive available exclusively in Victoria for commercial solar systems between 30 and 200 kW. VEECs are created under the Victorian Energy Upgrades program and represent ten years of deemed energy savings. Unlike STCs, VEECs do not diminish as 2030 approaches since the program operates on a fixed ten-year lifetime regardless of installation year.
The VEEC calculation uses one of two activity classifications. Activity 47A applies to systems up to 100 kW and uses an input factor of 0.13. Activity 47B covers systems from 100 to 200 kW with a higher input factor of 0.245, reflecting the greater energy displacement of larger systems. A regional factor of 1.04 applies to installations outside metropolitan Melbourne, providing a modest bonus for regional Victorian businesses.
Worked example: A 50 kW system in Melbourne (metro, Activity 47A) creates 50 × 0.13 × 10 × 1.0 = 65 VEECs. At a current price of approximately $72 per certificate, that delivers roughly $4,680 as an additional upfront discount on top of STCs. A regional installation in Geelong or Ballarat would generate 50 × 0.13 × 10 × 1.04 = 67.6 VEECs, or about $4,867.
Critically, VEECs stack with STCs for Victorian installations between 30 and 100 kW. This means a 50 kW system in Melbourne receives both the STC discount and the VEEC discount, making Victoria the most incentive-rich state for mid-range commercial solar. See the full VIC incentive breakdown.
LGCs: annual revenue for larger systems
Large-scale Generation Certificates apply to systems above 100 kW and operate on a fundamentally different model. Instead of a one-time upfront discount, LGCs are earned annually based on actual metered generation. One LGC is created for every megawatt-hour (MWh) of electricity your system produces, and these certificates are sold on the open market to entities with obligations under the Large-scale Renewable Energy Target.
Worked example: A 150 kW system in Brisbane (Queensland) producing approximately 340 MWh per year generates 340 LGCs annually. At a current market price of around $47 per certificate, that delivers approximately $16,000 in revenue each year for the life of the system. Over a 25-year system lifetime, LGC revenue can significantly outweigh the upfront STC value, though certificate prices fluctuate with market conditions.
LGC registration requires accreditation with the Clean Energy Regulator and metered generation data. Most businesses work with an LGC aggregator who handles the administration in exchange for a margin on the certificate price. See the full QLD incentive breakdown.
How incentives stack by state and system size
Not all incentives are mutually exclusive. The stacking rules depend on your state and system capacity:
- Victoria, 30–100 kW: STCs + VEECs. This is the highest-value combination for mid-range commercial systems. Both apply as upfront discounts and can be claimed simultaneously.
- Victoria, 100–200 kW: STCs on the first 100 kW + VEECs under Activity 47B on the full system capacity. The STC component caps at 100 kW, but VEECs cover the entire system.
- All other states, up to 100 kW: STCs only. No state-level scheme equivalent to VEECs currently exists in NSW, QLD, SA, or WA for commercial solar.
- Any state, above 100 kW: STCs on the first 100 kW (upfront) + LGCs on the full system output (annual). The STC and LGC schemes address different portions of the system and different time horizons.
For systems in the 80–120 kW range, modelling both scenarios (staying under 100 kW for maximum STC value versus going above 100 kW to unlock LGC revenue) is essential. The crossover point depends on your electricity consumption profile, export volumes, and how long you intend to hold the system.
Model it yourself
Adjust the system size below to see how STCs, VEECs, and LGCs apply to your installation. The calculator uses live certificate prices and automatically applies the correct zone multipliers and eligibility rules.
Next steps
The incentive landscape for commercial solar in Australia is generous but fragmented. Getting the numbers right requires matching your system size, location, and state-specific programs. Use the calculator above to run your own scenarios, or explore the detailed state-by-state breakdowns:
- Solar incentives hub — national overview and calculator
- New South Wales
- Victoria
- Queensland
- South Australia
- Western Australia