The certificate you see on a solar quote today has a quarter-century of history behind it. Understanding that history explains why the numbers move every January and why the scheme has a hard end date.
2001: the Mandatory Renewable Energy Target and the REC
The Mandatory Renewable Energy Target (MRET) began in April 2001. It required electricity retailers and other large buyers to source a share of their power from renewable generation, with a national target of an extra 9,500 GWh a year of renewable electricity by 2010. Proof of compliance was the Renewable Energy Certificate, or REC: one certificate for each megawatt hour of eligible renewable generation (or deemed generation).
Small solar systems were part of this from the start. An installer could create RECs up front for the electricity a rooftop system was expected to produce over its life, and sell them to fund a discount on the system. That “deeming” idea is still the heart of the scheme.
2009 to 2010: a bigger target and a bigger incentive
In 2009 the target was lifted to 20 per cent of electricity by 2020, in the order of 45,000 GWh, and a temporary multiplier was added to boost certificates for small solar. We cover that in the solar credits multiplier explainer.
1 January 2011: RECs split into STCs and LGCs
Rooftop solar was growing faster than the single market could handle. From 1 January 2011 the Renewable Energy Target was split in two:
- The Small-scale Renewable Energy Scheme (SRES) for rooftop solar, small wind and hydro, solar hot water and heat pumps. These systems create Small-scale Technology Certificates (STCs). Retailers must buy them, and the Clean Energy Regulator’s clearing house stands behind a $40 price ceiling.
- The Large-scale Renewable Energy Target (LRET) for power stations, which create Large-scale Generation Certificates (LGCs) based on metered output.
2012 to 2017: the multiplier ends and deeming starts to shrink
The solar credits multiplier stepped down and finished in mid-2013. In 2015 the large-scale target was revised down to 33,000 GWh by 2020. For small systems, the deeming period was 15 years in 2016 and then fell by one year every year from 2017.
2025 and 2026: batteries and mid-scale solar
The Cheaper Home Batteries Program began on 1 July 2025 and brought home batteries into the STC system. From 1 October 2026, solar above 100 kW and up to 1 MW also creates STCs with a fixed five-year deeming period (see mid-scale solar STCs).
2030: the end date
The scheme stops creating certificates for installations after 31 December 2030. For 2026 installs the deeming period is five years, four for 2027, and it reaches one year in 2030. The pattern is covered in the deeming period pillar page and why the rebate drops every year.
What this means for installers
The history matters for one practical reason: the certificate quantity is fixed at installation by the rules in force that day, not by the sale date. Check the year, zone and capacity with the STC calculator, lodge a complete claim, and see how STC trading works or the current pricing. The certificate trading glossary defines the terms used above.