Selecting the most appropriate feedstock for a specific purpose is vital in bioenergy projects. Feedstock selection depends on the following criteria:
- Required energy input
- Yields
- Ease of transformation
A lot of research is currently undertaken to improve the characteristics of the primary bioenergy feedstocks, whether they are plant-based or microbial populations.
Required energy input
One of the primary research areas in biological sources is the required energy input with respect to its overall output. Feedstocks are one of the steps that require a lot of energy, whether it is to build the optimal environment for microbial growth or to fertilize fields in order to improve its crop or wood biomass yields.
Research studies have shown that the energy inputs of corn ethanol are approximately 70-75% of the energy that will be produced by the combustion of its fuel because corn varieties have been bred in order to give high yields based on a high nitrogen amount (which requires fertilization). Current research is investing technologies to design methods that would lower the required fertilizer input and study new biological solutions to fertilization.
Dr. Donald L. Smith conducts research on the biofertilization of soils and plant root systems in order to decrease crop energy inputs.
Yields
It is of the utmost importance to select the species and enhance the feedstock in order to improve its overall yields. Higher yields can increase the size of certain operations or reduce the area or energy required to produce a specific amount of work. Through selective breeding, genetic engineering and by optimizing the environmental conditions, it is possible to decrease the detrimental impacts of bioenergy and to increase its efficiency and productivity.
Dr. Jaswinder Singh conducts various researches on plant breeding and genomics in order to obtain improved plant feedstocks.
Ease of transformation
A very good example of feedstock enhancement is the creation of canola (Brassica oleracea). Canola is a plant that has been bred from rapeseed in order to yield oils with a lower acid content; hence its name (Canadian oil, low acids). Its properties are similar to those of rapeseed, but it yields a vegetable oil that can be used more easily for human consumption.
When blended into a methyl ester (the transformation process in order to make biodiesel derived from methanol and vegetable oils), the main fatty acid contained in canola biodiesel is an 18-carbon chain (oleic acid). Rapeseed methyl ester, on the other hand, forms mainly 22-carbon chains (erucic acid). These bulkier fatty acids change the properties of the derived biodiesel and have an impact on the engine performance and fuel quality. One of the most important factors is that canola methyl esters have a lower viscosity than rapeseed methyl esters and therefore, are easier to burn in a combustion chamber. Canola methyl esters also had a lower acid content, but a slightly lower heat of combustion.
Overall, both fuels come from the same family and one species has been bred from the other, but the properties of their oils and methyl esters are slightly different. This affects the quality of the fuels they produce and the efficiency of their combustion.