This paper describes some of the main features and success factors of feed-in-tariffs (FiTs). When considering certain features of a FiT, policy makers should take into account the fact that investors will regularly look for three important parameters: transparency, longevity, and certainty. Any policy design that upholds these parameters while creating the right financial incentives and avoiding a prohibitive administrative burden will be more likely to attract investors than a design which provides the latter, but does not offer the same transparency and long-term certainty. The report furthermore outlines the policy developments in Germany to demonstrate the evolution of one of the most prominent FiT-systems in the world.