The STC discount is often the first question Australian solar customers ask — “how much is the rebate?” This guide provides the zone ratings, STC lookup tables by system size, and dollar value calculations to answer that question accurately for any Australian location and system size. See Solar Energy in Australia for more.
STC Zone Map: Zone by State and Region
| State/Territory | Region | STC Zone | Zone Rating |
|---|---|---|---|
| Northern Territory | All of NT (Darwin, Katherine, Alice Springs) | Zone 1 | 1.622 |
| Queensland | Cairns, Townsville, Mt Isa, Mackay (far north) | Zone 1 | 1.622 |
| Queensland | Brisbane, Gold Coast, Sunshine Coast, Toowoomba, Rockhampton | Zone 2 | 1.536 |
| South Australia | Outback and inland SA (Broken Hill area, Port Augusta) | Zone 2 | 1.536 |
| South Australia | Adelaide metropolitan and coastal SA | Zone 3 | 1.382 |
| Western Australia | Pilbara, Kimberley, inland WA | Zone 2 | 1.536 |
| Western Australia | Perth metropolitan and SW coastal WA | Zone 3 | 1.382 |
| New South Wales | Far west NSW (Broken Hill, Tibooburra) | Zone 2 | 1.536 |
| New South Wales | Sydney, Newcastle, Wollongong, Central Coast | Zone 3 | 1.382 |
| Australian Capital Territory | Canberra and surrounds | Zone 3 | 1.382 |
| Victoria | Melbourne metropolitan, Geelong, Ballarat | Zone 3 | 1.382 |
| Victoria | Gippsland, eastern highlands, southern VIC | Zone 4 | 1.185 |
| Tasmania | All of Tasmania (Hobart, Launceston, Devonport) | Zone 4 | 1.185 |
Note: Zone boundaries can vary within states. Use the Clean Energy Regulator’s postcode lookup for exact zone confirmation.
STC Count by System Size: Zone 3 (Sydney / Melbourne / Perth)
Deeming period: 4 years (2026). Zone rating: 1.382.
| System Size | STCs Created | Value at $37/STC | Value at $39/STC |
|---|---|---|---|
| 3 kW | 17 STCs | $629 | $663 |
| 5 kW | 28 STCs | $1,036 | $1,092 |
| 6.6 kW | 36 STCs | $1,332 | $1,404 |
| 10 kW | 55 STCs | $2,035 | $2,145 |
| 13.2 kW | 73 STCs | $2,701 | $2,847 |
| 20 kW | 111 STCs | $4,107 | $4,329 |
| 30 kW | 166 STCs | $6,142 | $6,474 |
STC Count by System Size: Zone 2 (Brisbane / Adelaide / Most of WA)
Deeming period: 4 years (2026). Zone rating: 1.536.
| System Size | STCs Created | Value at $37/STC | Value at $39/STC |
|---|---|---|---|
| 3 kW | 18 STCs | $666 | $702 |
| 5 kW | 31 STCs | $1,147 | $1,209 |
| 6.6 kW | 41 STCs | $1,517 | $1,599 |
| 10 kW | 61 STCs | $2,257 | $2,379 |
| 13.2 kW | 81 STCs | $2,997 | $3,159 |
| 20 kW | 123 STCs | $4,551 | $4,797 |
| 30 kW | 184 STCs | $6,808 | $7,176 |
STC Count by System Size: Zone 1 (Darwin / Far North QLD)
Deeming period: 4 years (2026). Zone rating: 1.622.
| System Size | STCs Created | Value at $37/STC | Value at $39/STC |
|---|---|---|---|
| 3 kW | 19 STCs | $703 | $741 |
| 5 kW | 32 STCs | $1,184 | $1,248 |
| 6.6 kW | 43 STCs | $1,591 | $1,677 |
| 10 kW | 65 STCs | $2,405 | $2,535 |
| 13.2 kW | 86 STCs | $3,182 | $3,354 |
| 20 kW | 130 STCs | $4,810 | $5,070 |
STC Count by System Size: Zone 4 (Tasmania / Southern VIC)
Deeming period: 4 years (2026). Zone rating: 1.185.
| System Size | STCs Created | Value at $37/STC | Value at $39/STC |
|---|---|---|---|
| 3 kW | 14 STCs | $518 | $546 |
| 5 kW | 24 STCs | $888 | $936 |
| 6.6 kW | 31 STCs | $1,147 | $1,209 |
| 10 kW | 47 STCs | $1,739 | $1,833 |
| 13.2 kW | 63 STCs | $2,331 | $2,457 |
| 20 kW | 95 STCs | $3,515 | $3,705 |
How Deeming Period Reduction Affects Value
The reduction in STC value as the scheme approaches 2030 is significant for customer decision-making:
| Year | Deeming Period | STCs (6.6 kW, Zone 3) | Value at $38/STC |
|---|---|---|---|
| 2026 | 4 years | 36 STCs | $1,368 |
| 2027 | 3 years | 27 STCs | $1,026 |
| 2028 | 2 years | 18 STCs | $684 |
| 2029 | 1 year | 9 STCs | $342 |
A customer who delays solar from 2026 to 2027 loses approximately $342 in STC value on a 6.6 kW Zone 3 system. This is a factual and legitimate point to include in proposals.
Pro Tip: STC Value Should Be Shown as a Separate Line in Every Proposal
Show the STC calculation transparently: “36 STCs × $38 = $1,368 STC discount.” Customers who understand exactly how the discount is calculated are more confident buyers than customers who see a vague “government rebate.” Use solar proposal software that automatically calculates STC count by zone and displays the value clearly in the financial summary.
Net System Cost Examples After STC Discount
Using a gross installed cost of $1,000/kW (mid-market 2026 pricing for a standard grid-connected system with quality components):
| System | Location | Gross Cost | STC Value | Net Cost |
|---|---|---|---|---|
| 6.6 kW | Sydney (Zone 3) | $6,600 | $1,368 | $5,232 |
| 6.6 kW | Brisbane (Zone 2) | $6,600 | $1,558 | $5,042 |
| 6.6 kW | Darwin (Zone 1) | $6,600 | $1,636 | $4,964 |
| 10 kW | Sydney (Zone 3) | $10,000 | $2,090 | $7,910 |
| 10 kW | Brisbane (Zone 2) | $10,000 | $2,318 | $7,682 |
| 13.2 kW | Melbourne (Zone 3) | $13,200 | $2,774 | $10,426 |
Payback Period with STC Discount
Using the net cost after STC and typical annual savings:
| System | Location | Net Cost | Annual Savings (est.) | Payback |
|---|---|---|---|---|
| 6.6 kW | Sydney | $5,232 | $1,800–2,200 | 2.4–2.9 years |
| 6.6 kW | Brisbane | $5,042 | $1,900–2,300 | 2.2–2.7 years |
| 6.6 kW | Melbourne | $5,232 | $1,600–2,000 | 2.6–3.3 years |
| 10 kW | Sydney | $7,910 | $2,700–3,300 | 2.4–2.9 years |
Annual savings assume retail electricity rate of $0.28–0.35/kWh, 70–80% self-consumption, feed-in tariff of $0.06–0.10/kWh for export.
Calculate Accurate STC Values for Every Australian Solar Proposal
SurgePV calculates the correct STC count by zone and deeming period, incorporates the STC discount into the financial model, and shows customers net cost, payback period, and 25-year savings in a single proposal output.
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Frequently Asked Questions
How do I calculate my STC count?
System kW × zone rating × 4 (deeming period in 2026). Zone 1: 1.622; Zone 2: 1.536; Zone 3: 1.382; Zone 4: 1.185.
What is the STC dollar value?
STCs × current market price (~$35–40 in 2026). A 6.6 kW Sydney system creates about 36 STCs worth approximately $1,300–1,400.
Does the STC value reduce each year?
Yes — by approximately 25% per year as the deeming period reduces from 4 (2026) to 1 (2029). Systems installed in 2026 receive the highest remaining STC value.
Can I sell my STCs myself?
Yes, through the REC Registry and clearing house. Most customers assign to the installer for an immediate upfront discount instead.
What zone is my postcode?
Use the Clean Energy Regulator’s postcode lookup at cleanenergyregulator.gov.au for the exact zone. The table above gives guidance by region — confirm with the official tool for any customer proposal.
