Small-Scale On-Farm Canola Biodiesel and Biofuel Assessment.

The ability of renewable energy sources to bridge the gap between declining petroleum resources and increasing global demand is in part predicated on the amount of net energy produced when all energy inputs and outputs of the system are considered.  This study was conducted to determine, through energy life cycle analysis (ELCA), the net energy ratio (NER), net energy balance (NEB), and net energy yield (NEY) of small-scale on-farm production of canola- [Brassica napus (L.)] and soybean-based [Glycine max (L.)] biodiesel and straight vegetable oil (SVO) biofuels in the upper Midwest.  Direct and embodied energy inputs based on well-defined system boundaries and contemporary data were used to estimate the energy requirement of crop production, oil extraction, and biofuel processing.  The NER of canola biodiesel was 1.78 compared with 2.05 for soybean biodiesel.  The NER of canola SVO was 2.11, whereas the NER for soybean SVO was 2.48.  Soybean-based biofuels, irrespective of type, were more energetically efficient than canola-based biofuels, stemming from a reduced requirement for nitrogen fertilizers.  Production of SVO biofuels was more energetically efficient than biodiesel regardless of feedstock due to the avoidance of energetically costly inputs expended in the biodiesel production process.  The NEY of canola-based biofuels were greater than that of soybean-based biofuels owning to the energy density of biofuel and meal, and the oil content of the comparative feedstocks.  A best-case scenario based on optimal yields, reduced fertilizer input, and advanced biofuel processing equipment indicated that the energetic efficiency of canola-based biofuels could be improved to a greater extent than soybean-based biofuels.  Small-scale on-farm biofuel production using canola and soybean can be an energetically efficient way to produce energy for on-farm use.