STC certificates for a Pakenham solar install.
What a Small-scale Technology Certificate actually is, how the deemed-energy number is calculated for Pakenham (zone 4, 1.382 multiplier), the 2026 spot price of around $36 per certificate, and how it's assigned to your installer so you see an upfront discount rather than wait for a payment.
The federal rebate hiding inside every solar quote.
Most Pakenham homeowners don't realise the biggest line item on their solar quote is a federal scheme called STCs - Small-scale Technology Certificates - created under the Renewable Energy Target Act 2000. It's the original solar rebate, predating Solar Victoria, predating the Cheaper Home Batteries Program, and still the largest single discount on a typical residential install.
The mechanism is simple. The federal Clean Energy Regulator issues one STC for every megawatt-hour your system is deemed to generate over the remaining years of the scheme. The system is given credit for the full deeming period upfront, so a 6.6kW system in Pakenham gets roughly 70-75 STCs created on installation day. Those certificates are tradeable - electricity retailers have a federal obligation to buy them - and the spot-market price is what translates the count into dollars on your quote.
The maths for Pakenham specifically.
Pakenham sits in solar zone 4 under the federal scheme, which uses a multiplier of 1.382 (zones 1 through 4 represent decreasing average solar resource - Pakenham is at the southern end of the band). The formula is:
STCs = System kW × Zone multiplier (1.382) × Deeming years
In 2026 the deeming period is 8 years (it was 10 in 2024 and steps down by one each calendar year until the scheme closes in 2030). So a 6.6kW Pakenham system in 2026 creates 6.6 x 1.382 x 8 = 73 STCs. A 10kW system creates 110 STCs. A 13.2kW system creates 146 STCs.
What the certificates are worth in 2026.
The STC spot-market price floats. Through 2025 and into 2026 it has been trading at around $36 per certificate, with a regulatory ceiling of $40 (a clearinghouse price set under the legislation). For most Pakenham quotes, the practical working number is $36 - that's what you'll see on our quotes and on any honest competitor's.
Applied to typical Pakenham system sizes in 2026:
- 6.6kW system - 73 STCs × $36 = $2,628 upfront rebate
- 10kW system - 110 STCs × $36 = $3,960 upfront rebate
- 13.2kW system - 146 STCs × $36 = $5,256 upfront rebate
That number gets subtracted directly off the gross install cost. It's not a tax credit, not a payment that arrives later - it's a discount that appears on the quote line marked "STC rebate" and reduces what you actually pay.
The fixed-dollar quote rule.
Demand a fixed dollar STC rebate on every quote you receive, not a phrase like "subject to STC price on install day" or "at current market rate." The market moves daily. A quote that locks in the dollar amount means the installer carries the market risk between sign-up and install; a quote that doesn't lock it in means you do, and if the price drops 10 percent you lose 10 percent of the rebate. We always lock the figure on the day you sign.
How the STC gets assigned to us (and why you won't see paperwork).
On installation day you sign a one-page form called an STC Assignment Form. It says: "I, the homeowner, transfer the rights to create and trade these STCs to Pakenham Solar & Battery, in exchange for the upfront discount shown on quote #XXXX." That's it. We then submit the certificates into the federal REC Registry within 12 months of install (required by law), they're validated against the Clean Energy Council install database, and once cleared we sell them to retailers via an STC trader.
The reason this exists - rather than you claiming the rebate yourself - is that the alternative would have you registering on the Clean Energy Regulator portal, lodging documents, waiting 3-6 months for clearance, and then trying to sell certificates yourself in a market you've never participated in. For the vast majority of homeowners, assigning to the installer is just better. You see the discount today; we carry the admin and the market risk.
Stacking STCs with other 2026 rebates.
The STC stacks. On a typical Pakenham retrofit in 2026 you can layer:
- Federal STC - $2,628 on a 6.6kW system (above)
- Solar Victoria Solar Homes rebate - $1,400 on solar panels for eligible households (income test applies), plus a matching interest-free loan up to $1,400
- Federal Cheaper Home Batteries Program - roughly $252 per usable kWh of battery, about $2,950 off a 12kWh BYD HVS or Sungrow, $3,400+ off a 13.5kWh Powerwall 3
- Solar Victoria interest-free battery loan - up to $8,800 toward battery purchase, repaid over 4 years zero interest
We model all of those together on the quote so you see one net out-of-pocket figure, with each rebate broken out as a line item. The combined effect on a full PV + battery retrofit in Pakenham right now is dramatic - the rebate stack is bigger than at any point in the scheme's history, and 2026 is the year of peak rebate before the deeming period and battery rebate both step down.
Want the STC + every other Pakenham rebate netted into one price?
We quote everything as a single net out-of-pocket figure, with STC, Solar Vic, Cheaper Home Batteries and any interest-free loan modelled in. CEC-accredited installer, Solar Victoria approved retailer, A-grade electrical.