In the EU, 20% of primary energy demand is to be covered by renewable energy sources by 2020 in order to reduce emissions of climate-relevant gases and dependence on imports of fossil energy sources. Biomass is the most important renewable energy source in both the European Union and Germany, with a share of around two thirds. Bioenergy sources play a major role in the expansion strategies for renewable energies. Biofuel and biogas production have risen sharply in Germany in recent years due to government subsidies. This part of bioenergy is essentially based on energy crop cultivation (mainly rapeseed and maize). However, with food prices rising sharply worldwide, especially in 2007/2008, the expansion targets for biofuels have been called into question to some extent. There was controversy about the extent to which the increasing production of biofuels had contributed to this price increase. With the financial and economic crisis, agricultural prices then fell significantly, and agriculture is in the midst of a revenue and income crisis in which energy crops can once again gain importance as an income option. Another point of discussion is the extent to which ambitious expansion targets will lead to the import of bioenergy sources and thus trigger an expansion of cultivated areas in tropical exporting countries at the expense of rainforest. ... mehrIn the case of large-scale rainforest clearing, this would even mean increased greenhouse gas emissions instead of their reduction. These rapid changes in the public debate pose particular challenges for scientific policy advice in this topic area. Subject and aim of the study The TA project "Opportunities and challenges of new energy crops" (short title "Energy Crops") was approved by the Committee on Education, Research and Technology Assessment on 27 September 2006. Due to the importance of the very complex topic and the manifold demands on the project, a staged approach was chosen. In the first phase of the project, the focus was on the review and comparative evaluation of existing studies. An overview of the subject area is provided in the basic analyses (TAB Working Report No. 121). The studies in the second project phase concentrated on the in-depth analysis of three topic areas: Expansion of energy crop use and (land) competition nationally and internationally, dimensions of environmentally compatible energy crop production, and certification of biogenic energy sources.