No, not for the federal ones. Both the federal solar STC rebate and the federal battery rebate are handled entirely by your installer. They create and sell the certificates on your behalf and pass the value to you as a discount on your quote, so you just pay the reduced price. The rebate shows up as a reduction in what you pay, not as a separate payment.

State programs work differently. The ACT Sustainable Household Scheme loan and the Home Energy Support rebates do require a separate application through the ACT Government before installation begins, so those need sorting in advance.