The Clean Energy Regulator dropped its annual administrative update for the Renewable Energy Target scheme, and while most of it is bureaucratic housekeeping, there are a few changes that affect solar buyers and installers.

I’ve read through the update so you can skip the legalese. Here are the key points.

STC deeming period adjusts again

As expected, the deeming period for Small-scale Technology Certificates has shortened by another year. Systems installed in 2026 now receive certificates based on four years of deemed generation (2026-2029), down from five years in 2025.

For a typical 6.6kW residential system, this means approximately 10-15 fewer STCs compared to installing the same system last year. At current certificate prices around $38-40, that’s roughly $400-600 less in upfront discount.

This isn’t news to anyone who’s been paying attention — the annual reduction has been built into the scheme since its inception. But it’s another data point for the “don’t wait to go solar” argument.

Compliance crackdown on installer documentation

The CER is tightening its audit procedures for STC claims. Starting mid-2026, a higher percentage of installations will be randomly audited for compliance with design and installation standards. Installers will need to provide more detailed documentation, including:

• Photographic evidence of completed installation
• Signed customer declaration confirming system details
• Proof of compliance with AS/NZS 5033 and AS/NZS 4777.2
• Evidence of appropriate sizing calculations

This is good news for consumers. Better auditing means fewer dodgy installations, and installers who cut corners face a higher risk of being caught. It may add a small amount of administrative cost to installations, but the quality improvement is worth it.

Battery eligibility clarifications

The CER has clarified rules around STC claims for systems that include battery storage. The key point: STCs are only generated by the solar panels themselves, not by the battery. However, the CER acknowledges that battery systems affect self-consumption patterns and has adjusted some of the deemed generation calculations to account for this.

In practice, this means no change in STC value for most installations. But it clears up some ambiguity that was causing confusion among installers and consumers.

Spot market for STCs

The STC clearing house price remains at $65.45 for 2026 (unchanged from the legislated cap). In practice, the open market price stays well below this — currently around $38-40 — because supply has consistently exceeded mandatory demand.

Some analysts are predicting STC prices could soften further as the deeming period shortens and fewer certificates are created per installation. But the market has been stable enough that dramatic drops seem unlikely in the near term.

What this means for solar buyers

If you’re planning to install solar in 2026, here’s the practical impact:

Your STC discount is smaller than it would have been last year. By about $400-600 for a typical residential system. This is the cost of waiting, and it happens every year.

Your installer may need more time for paperwork. The enhanced audit requirements mean some installers will take slightly longer to process STC claims. This shouldn’t affect your installation timeline, but be aware that the administrative process has more steps.

Quality should improve. Better auditing is a rising tide that lifts all boats. Marginal installers who relied on lax oversight will either improve or exit the market. Both outcomes are good for consumers.

The fundamental economics haven’t changed. Solar is still the best household investment in Australia. The STC reduction is annoying but small relative to the total value proposition. A 6.6kW system that saves you $1,300/year pays for itself in under five years, STC reduction or not.

The RET scheme is winding down by design — it was always meant to bootstrap the solar market and then fade away as the technology became self-sustaining. We’re in the late stages of that process, and solar has thoroughly proven it doesn’t need large subsidies to compete. The remaining STCs are nice to have, but they’re no longer the main reason to go solar.