Biofuels have long been considered to play a key role in climate protection in transport. This role was significantly reduced by the discussion on food vs. fuel. At present, biofuels are again increasingly being brought into the discussion as a central solution in view of the difficulties in achieving climate protection targets in the transport sector. This study, commissioned by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU), is intended to shed light on the potential and limitations of biofuels and to summarise them in a compact form. The following questions will be answered: What is the fuel produced from, what quantities and types of plants are processed, where do they come from and how much arable land is it used for? What are the limits for biofuels from arable land and for biofuels from waste and residues?