Overview of the challenges in the production of biodiesel

This paper presents an overview of the main challenges in the production of biodiesel. Whereas the cost of biodiesel is determined for about 85 % by the cost of the raw material and that the most employed feedstock are oils used also for nutrition, it seems obvious that it is necessary to search for nonedible feedstock with low cost for the production of biodiesel. The choice of feedstock is based on variables such as the oil yield, local availability, cost, and government support. Feedstocks with higher oil yields are more preferable in the biodiesel industry because they can reduce the production cost. In Brazil, approximately 80 % of the biodiesel produced is made from soybean despite of its low oil content (18–21 %). The leadership of soybeans as feedstock for biodiesel production is explained by the increasing demand for more protein meal. Coconut and babassu with more oil yield respectively with 62 and 60 % of oil content are likely substitutes for soybean. Castor bean, despite of its high oil content (50 %) and advantages, such as low production cost and its resistance to hydric stress, has some difficulties to meet the ANP regulations, mainly due to its high viscosity. However, castor bean biodiesel-diesel blends of up to 40 % are within specifications. Yield per hectare is another factor that should be considered in the choice of raw material for the production of biodiesel. Among the various oilseeds, oil palm deserves to be highlighted as the most productive.