Only a small number of pretreatment methods has been reported as being potentially cost-effective. These include steam explosion, liquid hot water, concentrated acid hydrolysis (Groenestijn et al.), and dilute acid pretreatments (Mosier et al., 2005). At the moment the production of ethanol from lignocel-lulose is growing rapidly, and by looking at the industrial activities in this field more knowledge can be gained on the applied pretreatment methods. The International Energy Agency (IEA) has a Bio-energy Task 39 entitled ‘Commercializing 1st and 2nd generation Liquid Biofuels from Biomass’. An overview by Bacovsky shows demonstration plants worldwide for the production of biofuels and ap-plied pretreatment methods (Bacovsky, 2009). Two main pathways are defined: biochemical conver-sion and thermochemical conversion (e.g. gasification and combined pathways).