Grass Biofuel Pellets
Growing Interest in Grass Biofuels: An ecological response to energy concerns
Sharp increases in oil, natural gas, propane, and some regional electricity prices during the last ten years have demonstrated consumer vulnerability to fluctuations in energy supply. Farmers are particularly vulnerable because as primary producers they are often expected to swallow higher energy costs. These high energy prices combined with low food commodity prices represent a double threat to the prosperity of farmers worldwide.
One solution to resolve these problems would be to commercialize renewable biofuel crops. By doing this, it would help diversify the farm economy, as well as allow farmers to increase their energy self-reliance and control their energy costs.
 The need to find alternatives to fossil fuels and reduce Greenhouse Gas emissions has peaked interest in biofuels by energy specialists around the world. REAP-Canada has pioneered the research and development of biofuel pellets made from switchgrass (Panicum virgatum) for use in space heating applications. Switchgrass, when pelletized, has considerable potential to displace oil, natural gas, and electricity used for heating fuel. This development can significantly reduce greenhouse gases and heating costs and sustainably assist the development of rural communities. Fast growing warm season perennial grasses have been identified as ideal candidates for biomass fuel production due to their high net energy yield per hectare and low cost of production. Switchgrass is one type of warm season perennial grass native to the Great Plains and eastern North America. It is favourably viewed as it easily adapts to marginal soils and arid climates with minimal fertility and management requirements.
Converting switchgrass into a viable energy option suitable for widespread application requires an energetically efficient, economical, and convenient energy transformation pathway to meet consumer energy needs. The recent development of gasifier pellet stoves and furnaces (see www.pelletstove.com) provides a practical pathway for grass biofuel pellets to be converted into heating energy. These appliances are capable of burning moderately high ash pelleted agricultural fuels at 81-87% efficiency. In this system, switchgrass pellets are used much like wood pellets and provide fuel conversion efficiencies and particulate emissions in the same range as modern oil furnaces. When burned in the gasifier stoves and furnaces, pelleted switchgrass provides fuel conversion efficiencies and particulate emissions in the same range as modern oil furnaces. Each GJ of grass pellet energy directly substitutes for one GJ of oil, and can be utilized on a large scale without significant air pollution. The pelletized grass biofuel systems builds on, and is likely to overtake, the existing wood pellet heating industry which is rapidly developing without any significant level of government intervention. Pelletized grass biofuel is poised to become a major fuel source because it is capable of meeting some heating requirements at less cost than all available alternatives. The cost-effectiveness of pelletized grass as a fuel results from:
- efficient use of low cost marginal farmland for solar energy collection
- minimal fossil fuel input in field production and energy conversion
- replacement of expensive high-grade energy forms in space and water heating
- minimal biomass quality upgrading which limits energy loss from the feedstock
- efficient combustion in advanced, affordable, and user-friendly devices
Grass pellets burned in gasifier pellet stove
REAP-Canada conducts agronomic research on switchgrass cultivars under different growing conditions to determine the optimum strain suitable for large scale production as an energy source. Adaptability trials assess which varieties are best suited to the growing conditions and able to grow with minimal fertilizer inputs.
Roger Samson, Executive Director, and a promising switchgrass variety |
Some strains of switchgrass grow tall and contain a bluish green color. We suspect they are nitrogen-fixing. |
View of several switchgrass plots. A great variation in phenotype can be observed between plots |
Contrary to the prevailing wisdom that reducing GHG emissions will raise societal energy costs, pelletized or briquetted biofuels can provide consumers with lower and more stable heating costs while dramatically cutting GHG emissions. Given that agricultural commodity prices are declining in real dollars, pellet and briquette fuels are likely to become cheaper over time. By contrast, wood-based pellets have been rising in cost due to ongoing improvement in industrial wood utilization, which is reducing the waste fraction of delivered roundwood. Furthermore, the development of a grass pellet biofuel industry has great potential to revitalize rural economies by absorbing the surplus production of the agricultural sector, and cutting on-farm fuel costs in heating intensive sectors like greenhouses.
During combustion of plant-based biofuels, the carbon dioxide emitted is considered to be sequestered during the growth cycle of the plant. Carbon emissions are largely neutral except for energy associated with their production and conversion into fuel pellets. The savings in GHG emissions is considerable because pellets (at 5 kg CO2e/GJ) have much lower emissions than coal (96 kg CO2e/GJ) and natural gas (62.13 kg CO2e/GJ). To learn more grass biofuels, view powerpoint presentations on:
The Potential for Energy Farming with Grasses in North America
 The 1.1 billion acres of farmland in North America could be used to create a renewable source if currently viable biofuel production systems were expanded. In most agricultural regions, warm season grasses can be grown for $2-3 USD/GJ. Much of this farmland can collect 100-250 GJ of energy per hectare with existing production technology and plant materials. Efforts have been made to produce power and liquid fuels from this material, but the development strategies appear not to be economically sustainable. Converting this feedstock into a viable energy option suitable for widespread application requires an energy efficient, economical, and convenient energy transformation pathway to meet consumer energy needs.
Of the farmland in North America (932 and 168 million acres in the US and Canada respectively), we estimate that 150 million acres could be dedicated to energy farming without appreciably affecting North America's food supply. Assuming biomass energy crop yields are 50% higher than the current hay yields, harvested perennial grass yields of 5.9 and 8.1 tonnes/ha in Canada and the US respectively can be expected. By energy farming 130 million acres in the US and 23.4 million acres in Canada, a total production capacity of 424 and 55 million tonnes could be achieved in the two respective countries. Assuming grass fuel pellets contain 18.5 GJ of energy/tonne, 8.9 billion GJ (an energy equivalent of 1.5 billion barrels of oil) could be produced each year from energy crop production on 14% of North American farmland. With U.S. crude oil imports of approximately 3.4 billion barrels per year, the U.S. could displace the equivalent of 39% of its oil imports by growing biofuels on 14% of its farmland.
The most promising regions to develop a grass pellet fuel industry are those where hay production costs are low and heating costs are high due to long winters and high fuel costs. Based on hay prices, land costs, relative winter heat costs, and warm season grass performance data in North America, the best opportunities exist in the states of North Dakota, South Dakota, Nebraska, Minnesota, Wisconsin, and the provinces of Manitoba, Ontario, and Quebec.
 An ideal location for a biofuel pellet industry is the province of Manitoba. This largely agricultural province has amongst the lowest hay prices in North America and no indigenous fossil energy reserves. The spread between delivered heat costs of conventional energy sources and hay costs is rapidly growing. In real dollars, long-term hay prices remain flat at $2 USD/GJ ($35 USD/tonne) while delivered heat costs for natural gas, oil and electricity are rising and are now in the $10-13 USD/GJ range. With current pellet production costs estimated to be $2/GJ ($35 USD/tonne) and a conversion efficiency of 80%, delivered heat costs for on-farm and residential grass pellet fuels are projected to be in the $5-7.50 USD/GJ range. There are major opportunities for Manitoba households to switch from electrical heating (used by 32% of households) to biofuel heating systems. Widespread implementation of this energy substitution strategy would enable hydro-rich provinces, such as Manitoba and Quebec, to expand electricity exports into the US market.
Documents published regarding REAP's bioenergy projects are located in the on-line library.
(C) 2004 REAP-Canada
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