Small-scale Technology Certificates (STCs) are an Australian Government incentive that can reduce the upfront price of an eligible solar PV system; they are not usually paid as a direct cash rebate to the homeowner. The potential discount depends on the system’s size, location, installation year, remaining deeming period and the certificate price, so it can change over time. An installer accredited by the Clean Energy Council generally handles creating and transferring the STCs, with the value shown in your quote. Check the quote carefully and confirm current eligibility through the Clean Energy Regulator or energy.gov.au.