The use of crop residues for biofuel production

Abstract Fossil fuels are a finite source of energy and are going to deplete with the passage of time, possibly running out in a couple of decades. The importance of environmentally friendly biofuels has been realized in the last few decades. The climate and global warming issues associated with burning fossil fuels provide the initiative to look for a substitute fuel to meet the energy demand in the future. Generally, biomass is considered as a new energy source and has sufficient energy value per unit mass, but which is lower than that of fossil fuels. The use of biomass as a valuable energy source is a promising area of interest for researchers. Biomass is a renewable feedstock used to produce biofuels (in solid, liquid, and gas forms) for sustainable development in the future. A variety of crop residues are being produced around the world that can be converted into biofuels using different treatment and production methods, such as thermochemical conversion (e.g., combustion, pyrolysis, hydrothermal liquefaction, and gasification), biochemical conversion (e.g., microbial fermentation, enzymatic hydrolysis, and anaerobic digestion), and chemical treatment (e.g., transesterification). However, concerns such as environmental forfeits of contending uses of crop residues must be evaluated with short- and long-term perception considering its impact on agricultural land and biofuel production.