Biofuels which are now in use have problems with current engine technology and incompatible to be used without blending. It has to be blended in low ratios to fossil fuels. Now, a modern generation drop-in-biofuel can contain high hydrogen to carbon ratio with no or low sulphur and oxygen content, low water solubility and high carbon bond saturation. It can be made from sugars and alcohol via biochemical conversion -trans-esterification, lignocellulosic biomass via thermochemical process.
It can also be produced by a hybrid process of all the above. Some advantage are low sulphur content and thereby low harmful emissions, high saturates and low residues and high cetane value for reduced knocking. Now such drop-in-biofuels can be produced from residues, woody biomass, and dedicated energy crops. The most favourable crop are having high sugar content like sugarcane, sweet sorghum etc.,