A feed-in tariff (FIT) is a policy instrument that encourages investment in renewable energy sources in order to reduce emissions, improve energy security and meet climate change commitments. It does this by providing producers of renewable energy with a guaranteed, above-market price for the electricity they produce.

The main feature of a FIT is that it guarantees a predetermined price for renewable energy that producers can count on for the long term. This guarantee encourages manufacturers to produce and continuously maintain renewable energy sources, since they can be assured of the revenues from their electricity in advance. The time period for a FIT usually ranges from 15 to 20 years, allowing producers to have the assurance of long-term contracts.

FITs are used in many countries throughout the world, including the United States and Germany. Japan is particularly well known for its FITs, which was put in place in 2012 to promote investment into renewable energy sources, including wind, solar and hydropower. FITs are also used in other countries such as France, China and India.

In the United States, FITs are typically provided at the state level and vary depending on the specific laws. FITs generally aim to encourage investment in renewable energy by providing a secure and stable source of revenue that is above regular energy prices. In some cases, they also offer additional incentives, such as production incentives and loan guarantees.

FITs have been proven to be effective in encouraging investment and growing the renewable energy industry. In fact, Germany has been able to achieve 90% of its renewable energy target through its FIT policy. The success of FITs have also led to their adoption in many other countries around the world, as governments increasingly seek to reduce emissions and better their energy security.

Overall, feeding into tariffs are an effective policy tool to support the development of renewable energy sources, as they provide producers with a guaranteed, above-market price which is intended to encourage investment. FITs have been used in many countries around the world, with notable success in Germany, Japan, and the United States, and they continue to be an important part of government policy strategies to support renewable energy development.