Solar panel installation costs in Australia vary with system size, panel and inverter quality, roof access, location and installation complexity. As a broad guide, a standard grid-connected system may cost several thousand dollars after any applicable federal STC discount, while adding a battery can substantially increase the total. Your final price also depends on the installer, available rebates and whether switchboard or electrical upgrades are needed. Compare detailed quotes from appropriately accredited installers and check current incentives through energy.gov.au or your state government.