In Australia, the main federal solar discount in 2026 is generally linked to Small-scale Technology Certificates (STCs), which are calculated using system capacity, location and installation year. Eligible systems are typically no larger than 100 kW, but the certificate value and any upfront discount can vary with market conditions and the installer’s terms. State or territory programs may have separate size limits and eligibility rules, while battery incentives are a different scheme. Check the current details on energy.gov.au and ask an accredited installer to calculate the applicable amount for your property.