policies supporting biofuels which are mainly used in transportation were thus blamed for spikes in food prices in and oecd growing food crops for conversion into a biofuel eg ethanol in a refinery for subsequent combustion in a power plant will have different landuse impacts from growing woody crops for direct combustion in addition the efficiency of bioelectricity processes vary while woody crops yield more biomass per unit area than a food crop like corn or soybean biofuelrelated processes like ethanol combustion usually convert a higher percentage of biomass energy content into electricity fthenakis and kim