For more than 20 years, efforts have been made to grow dedicated biomass crops such as switchgrass, but no economically viable, energetically efficient transformation pathway has been described to convert this material into a usable energy form to displace fossil fuels. To meet this goal, it is proposed that warm-season grasses such as switchgrass be used for heat-related energy applications. This is considered to be the energy use with the highest comparative advantage for switchgrass, as the application requires little upgrading of the original energy quality of switchgrass, and it best matches the widespread production of the crop in North America. To improve combustion efficiency, the biomass quality of switchgrass can be upgraded through cultural management practices to reduce the chlorine, potassium, and silica content of the fuel. Densification of the grass into a pellet form appears economically attractive and is essential to create highly controlled combustion for space-heating applications.
Switchgrass pellets can be converted into usable heat at 82-84% efficiency in a close-coupled gasifier pellet stove designed to handle moderately high ash fuels. Relative to oil and natural gas systems, switchgrass pellets have the potential to reduce fuel-heating costs and greenhouse gas emissions in eastern Canada by approximately 30% and 90%, respectively. Compared to all other biofuel production and energy-transformation pathways currently proposed, switchgrass pellet heating offers the highest net energy yield per hectare, the highest energy output-to-input ratio, the greatest economic advantage over fossil fuels, and the most significant potential to offset greenhouse gases."
