A solar feed-in tariff (FiT) is a credit your electricity retailer may provide for surplus solar power exported to the grid. The rate and contract conditions vary by retailer, state or territory, and energy plan, and may change over time. Your bill usually also includes usage charges, supply charges and other conditions, so the highest FiT is not always the cheapest overall option. Compare current offers through your retailer or an official comparison service, and check your contract before switching.