Part of grasslands in Northwest Europe is no longer needed for animal husbandry and could be used to support the energy transition towards renewable energies. For assessing the possible contribution of the feedstock grass, a new improved model based on a Geographic Information System (GIS) has been developed and applied to the model regions in the United Kingdom, the Netherlands, Belgium, France, and Germany within the INTERREG project BioenNW - Delivering Local Bioenergy to Northwest Europe. The grassland-to-energy model links geospatial maps data with agricultural data which had been made available by European, national, and regional authorities. The spatially differentiated grass yields rely on an elevation and soil-based classification. The so-called surplus grass is available for energy conversion after satisfying first existing fodder demands from animal husbandry, and secondly environmental sustainability criteria representing a weak sustainability (Basis) scenario and a strong sustainability (Restrict) scenario. The results show large potentials which vary strongly between the model regions. Local biomass potentials account for up to 1416 tonnes per square kilometre dry mass (t/km(2) dm) per year in the Basis scenario in South Netherlands, while the annual mean values for the regions vary between 100 t/km(2) dm in Ile de France and 374 tikm(2) dm in the West Midlands region. Five out of seven regions show surplus grass in the Basis scenario; four regions even in the Restrict scenario. Thus, the model approach provides improved quality and consistency in biomass assessment at different scales and for different regions in the EU. (C) 2017 Elsevier Ltd. All rights reserved.