is the payment that you get when one of the renewable energy (wind, solar, etc..) that you use generates excess electricity, when the excess electricity goes to the grid from your house it’s when you get paid for this extra electricity which is sent into the grid.

Feed-in tariffs are seen as necessary to promote renewable energy sources in early stages of their development, when production is often not economically feasible. Feed-in tariffs usually involve long-term agreements and prices tied to the cost of production of the energy in question, and it is usually between 15-25 years. The long-term contracts and guaranteed prices shelter producers from some of the risks inherent in renewable energy production, encouraging investment and development that otherwise might not take place.