On November 12 2014, PBL – Netherlands Environmental Assessment Agency published a report on ILUC (indirect land use change) of first generation biofuel production: Struggling to deal with uncertainties What is known about indirect land-use change? Koen Overmars Consultancy co-authored this report. In this report the main uncertainties of ILUC calculation are described in a clear and understandable manner. The report illustrates this with examples from recent literature. Additionally, the report presents a new approach to quantify ILUC. ILUC is not calculated as gCO2/MJ, but as an effort in one of the determining factors (yield increase, reduced consumption) in order to achieve a certain ILUC level.