Battery Costs, Rebates and 2026 Rules
Cheaper Home Batteries Program STC factor: the 2026–2030 table and the 14/28/50 kWh tiers
How the battery STC factor works after 1 May 2026 — the six-monthly step-downs to 2030, the 14, 28 and 50 kWh tiers, worked examples and why the install date matters.
The STC factor is the number of small-scale technology certificates a home battery can create for each kWh of usable capacity under the Cheaper Home Batteries Program. For batteries installed from 1 May to 31 December 2026 it is 6.8. It falls to 5.7 for installations from 1 January to 30 June 2027 and keeps stepping down every six months until it reaches 2.1 in the second half of 2030. Since 1 May 2026 the factor also tapers by size: the first 14 kWh count in full, kWh above 14 up to 28 count at 60%, kWh above 28 up to 50 count at 15%, and anything above 50 kWh counts for nothing. Multiply the result by the STC price to get the discount in dollars.
This guide sets out the published table, shows the arithmetic and explains the timing traps. For the wider picture, start with the 2026 battery rebate overview.
The published STC factor table
The Clean Energy Regulator (CER) publishes the factors on its solar batteries and STC entitlement pages (checked 27 October 2026). The values for 2026 onwards are:
| Installation period | STC factor per usable kWh |
|---|---|
| 1 Jan – 30 Apr 2026 | 8.4 |
| 1 May – 31 Dec 2026 | 6.8 |
| 1 Jan – 30 Jun 2027 | 5.7 |
| 1 Jul – 31 Dec 2027 | 5.2 |
| 1 Jan – 30 Jun 2028 | 4.6 |
| 1 Jul – 31 Dec 2028 | 4.1 |
| 1 Jan – 30 Jun 2029 | 3.6 |
| 1 Jul – 31 Dec 2029 | 3.1 |
| 1 Jan – 30 Jun 2030 | 2.6 |
| 1 Jul – 31 Dec 2030 | 2.1 |
The change on 1 May 2026 was announced by the government on 13 December 2025 and made by regulation in early 2026 (the Renewable Energy Legislation Amendment (2026 Measures No. 1) Regulations 2026 contain a schedule of amendments relating to the program). The CER says the factor is set to track falling battery costs so that the discount stays at around 30% of upfront cost.
The size tiers since 1 May 2026
Before May 2026, every eligible kWh up to the cap earned the same factor, which encouraged very large batteries. The tiered rule now applies:
| Part of usable capacity | Share of the factor applied |
|---|---|
| 0 to 14 kWh (inclusive) | 100% |
| Above 14 up to 28 kWh (inclusive) | 60% |
| Above 28 up to 50 kWh (inclusive) | 15% |
| Above 50 kWh | 0% (not eligible for STCs) |
The battery itself can still be up to 100 kWh nominal; only the certificate calculation stops at 50 kWh.
Converting capacity to "effective kWh"
The easiest way to apply the tiers is to convert usable capacity into effective kWh, then multiply by the factor.
| Usable capacity | Effective kWh | Certificates at 6.8 | Value at an illustrative $36 |
|---|---|---|---|
| 5 kWh | 5 | 34 | $1,224 |
| 10 kWh | 10 | 68 | $2,448 |
| 13.5 kWh | 13.5 | 91 | $3,276 |
| 20 kWh | 14 + 6 × 0.6 = 17.6 | 119 | $4,284 |
| 28 kWh | 14 + 14 × 0.6 = 22.4 | 152 | $5,472 |
| 40 kWh | 22.4 + 12 × 0.15 = 24.2 | 164 | $5,904 |
| 60 kWh | 22.4 + 22 × 0.15 = 25.7 | 174 | $6,264 |
Certificates are shown rounded down to whole numbers; the CER's online STC calculator gives the authoritative count for a specific battery. The STC price is illustrative: the CER describes a usual range of about $33–$38 but does not set it.
The pattern is clear. The step from 13.5 to 28 kWh more than doubles the capacity but adds only about 67% to the discount, and going from 28 to 60 kWh adds about 14%. For most households, sizing to the first tier or a little above makes the most of the discount per dollar spent.
Why the installation date matters more than the signing date
The CER said in March 2026 that rebates are determined by the installation date, not the date a contract is signed, and warned retailers not to rush installations or promise dates they could not meet. The same logic applies at every six-monthly step.
Worked example (illustrative): a 13.5 kWh battery quoted in December 2026.
- Installed by 31 December 2026: 13.5 × 6.8 = 91 certificates, about $3,276 at $36
- Installed in January 2027: 13.5 × 5.7 = 76 certificates, about $2,736 at $36
- Difference: about $540 more to pay
What to ask for in writing:
- The expected installation date and what happens to the price if it slips into the next period.
- Whether the quoted discount assumes the current factor or the next one.
- The number of STCs and the price per STC the installer is using.
The CER has also said retailers must honour contracts they sign and give accurate quotes that reflect the changes. If a retailer tries to raise the price after signing because the factor changed, check the contract terms and contact your state fair trading agency; see where to get help.
What the factor does not include
The STC factor only covers the federal discount. It does not include:
- Solar panel STCs, which use a different formula based on kW, postcode zone and deeming years — see solar STCs and the 2030 end
- State incentives, such as the NSW VPP incentive or WA Residential Battery Scheme — see state battery incentives
- Agent fees: your discount is what the agent pays you for the certificates, which may be below the market price
Eligibility conditions also have to be met for any certificates to be created: approved battery, VPP-capable, accredited installer and only one battery per NMI. See the eligibility guide.
Expansions and stackable batteries
The CER allows an existing battery to be expanded, provided at least 5 kWh is added and total nominal capacity including the existing battery stays at or below 100 kWh. For stackable systems, only the newly added modules can be claimed and the whole system must be re-certified. Ask your installer how the tiers apply to the added capacity before you assume a full-factor discount on the expansion.
FAQ
Is the STC factor the same everywhere in Australia?
Yes. Unlike solar panel STCs, the battery factor does not depend on your postcode zone. It depends on usable capacity and installation date.
Does nominal or usable capacity count?
Usable capacity counts for the certificate calculation. Nominal capacity is used for the 5–100 kWh size limits. Ask for both figures on the quote.
Could the factor change again before 2030?
The table is set in regulations and has already been changed once. Check the CER's solar batteries page before you sign, especially if your installation is months away.
Where do I check the number of certificates?
Use the CER's STC calculator on cer.gov.au, or the discount estimator on this site for a quick range.
Sources
- Clean Energy Regulator — solar batteries page, STC entitlement table, March 2026 notice on the 1 May changes
- Federal Register of Legislation — Renewable Energy Legislation Amendment (2026 Measures No. 1) Regulations 2026
- Department of Climate Change, Energy, the Environment and Water — program policy and funding
