Life cycle assessment (LCA) methodology is increasingly used to determine the potential environmental impacts of biofuels and bioenergy. This paper presents the outcomes of screening LCAs of 13 future energy crops for Europe summarizing the results of the EC-funded project 4F CROPS -Future Crops for Food, Feed, Fiber and Fuel. For analysis, these dedicated energy crops -representing seven environmental zones in Europe -are combined with a multitude of processing and utilization options, resulting in 120 different biofuel and bioenergy chains. Compared to fossil fuels and energy carriers, all biofuel and bioenergy chains show environmental advantages in terms of life-cycle energy use and greenhouse gas (GHG) emissions but mostly disadvantages regarding other environmental impact categories. Quantitative results vary widely across environmental zones, depending on crop species, agricultural inputs, and yield. Moreover, coproduct accounting and coproduct utilization, as well as the agricultural and fossil reference system play an important role. In view of environmental advantages and disadvantages, subjective trade-offs are required between the environmental impact categories. If saving GHG emissions is given the highest environmental priority, combined heat and power generation from herbaceous lignocellulosic crops is the most effi cient option in terms of land use, provided that the biomass is cultivated on surplus agricultural land, thus avoiding indirect land-use change.

Bioenergy is an important renewable energy carrier with uncertainties in future development due to sustainability issues. Its further development requires a robust bioenergy strategy on a national level. To provide these strategy elements, a dedicated approach was developed, which includes a new modeling framework, an impact assessment, and stakeholder involvement. Demonstrating the approach on the example of Germany, four bioenergy utilization scenarios for a period up to 2050 have been assessed using seven indicators that cover aspects from local infrastructure to global food security. The devised strategy elements address the national and international feedstock supply, promising fields of utilization, and appropriate frame conditions. The results coherently focus on a wide range of policy fields, which has not been possible in the past. IntroductionBioenergy is made from renewable biomass sources. In recent decades, it has been the most significant renewable energy carrier in Germany, Europe, and the world [1][2][3]. On a global level, bioenergy counts today for 100 % of the renewable transport fuels, over 90 % of modern renewable heat, and 8 % of renewable power [3], with a significant rise in bioenergy utilization through all sectors, which means a doubling of the use between 2006 and 2014, and significantly contribute to global greenhouse gas (GHG) emission reduction [4]. Advanced renewable energy goals and the availability of a wider spectrum of costefficient renewable energy technologies, i.e., wind power, photovoltaics, heat pumps, and e-mobility, mean the role of bioenergy in future energy systems is expected to change [5][6][7]. However, concerns have also arisen about the availability of feedstock to cover additional energy demands using bio-based energy carriers. Although biomass is a renewable resource, its availability is limited at a certain point in time, especially when environmental impacts on biodiversity, soil quality, natural carbon stocks and sinks, e.g., are taken into account [8][9][10]. Nevertheless, the rise in the demand for biomass for food production, feed production, and material use is expected to continue in the future [11][12][13][14]. It is commonly agreed that bioenergy has to be utilized in line with the goals of sustainable development; in particular, food security ranks higher than using biomass for energetic purposes [15,16].

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