Solar panels use photovoltaic cells to convert sunlight into direct-current electricity, which an inverter changes into the alternating current used by Australian homes. Your appliances generally use the solar power first; extra electricity may be sent to the grid for a feed-in tariff or stored in a battery if you have one. When solar output is low, such as overnight or during heavy cloud, your home can draw electricity from the grid or battery. Actual output, system costs and savings depend on your roof, location, electricity use and installer’s design, so compare quotes and check energy.gov.au.