The Biomass R&D Technical Advisory Committee, a panel established by the U.S. Congress to guide future development of federally funded bioenergy research and development, envisions 30 percent replacement of current U.S. petroleum consumption with biofuels by 2030 under a plan that would require about a billion tons of dry biomass feedstock per year. Of feedstock crops, none is more promising than switchgrass.

 

The strategy, spelled out in a report issued by the Department of Agriculture (USDA) and Oak Ridge National Laboratory of the Department of Energy, suggests that a portfolio consisting of 30 percent agricultural waste, 35 percent forest, 5 percent grains to biofuel, and 30 percent "specialized crops" could meet this objective within a generation, reducing demand for imported oil, curbing missions of greenhouse gases, and strengthening the country's farm economy.

 

Switchgrass is a better source for cellulosic ethanol production, a more efficient and less polluting process than traditional corn-based ethanol production.

 

Cellulosic ethanol is a blend of normal ethanol that is derived from cellulose, the main structural component of plants, and can be produced from virtually any plant matter including agricultural waste.

 

Since such wastes are typically burned or discarded—adding to agricultural production costs as well as carbon emissions to the atmosphere—their utilization as fuel is specially efficient.

 

According to DOE studies, cellulosic ethanol may reduce greenhouse gas missions by 85 percent over reformulated gasoline, while offering significantly higher energy yields and low emissions than sugar and corn-derived ethanol.

 

Further, since cellulose cannot be digested by humans, its production does not directly compete with food production and produces considerably higher yields than traditional grain crops.

 

Plants like switchgrass are excellent feedstock for cellulosic ethanol production and can be planted on marginal agricultural lands.

 

Switchgrass, a perennial grass that once blanketed the central prairies and eastern parts of the United States from the Gulf Coast to Canada, offers perhaps the best potential as a source of biofuel in America.

 

Studies conducted at Auburn University found the plant yielded an average of 11.5 tons per acres over a five-year period, enough to make 1,150 gallons of ethanol per acre per year (1,750 liters per hectare per year), or more than three times the yield of traditional corn-based ethanol.

 

Further, once you factor in the energy required for tractors, transport, and fertilizers, the net energy output of switchgrass is 15 to 20 times better than corn’s. In other words, it requires far less land and energy to produce a gallon of fuel derived from switchgrass than it does from corn, sugar, or soy.

 

Beyond efficiency, switchgrass offers advantages over gasoline and standard ethanol. Hardy and adaptable, as a perennial, switchgrass can be harvested as a cash crop on an annual or semi-annual basis without replanting for 10 years.

 

The species has multiple uses—ethanol feedstock, forage, ground cover—giving a farmer several options depending on market conditions. It can be also utilized for chemical products useful for making fertilizers, solvents, and plastics.

 

The plant can be harvested with standard farming equipment, requiring minimal additional capital investment for farmers. From an ecological standpoint, unlike annuals which deplete soil of nutrients, switchgrass restores organic nutrients to over-farmed and otherwise degraded lands.

 

Further, the plant's deep roots anchor soil, reducing erosion and filtering runoff before it enters waterways.

 

While switchgrass looks promising in its natural form, through selective breeding researchers at leading universities are working to boost yields and increase the adaptability of the plant for growing under a variety of conditions while reducing the need for chemical fertilizers.

 

A study released recently by Carnegie Mellon found that ethanol derived from switchgrass could be made in sufficient quantities to deliver 16 percent ethanol fuel to all consumers in the U.S. by 2020.

 

Source: LIOR International 

 

Editorial comment: Guides to the cultivation of switchgrass can be found here: http://bioenergy.ornl.gov/papers/bioen98/teel.htm and here: http://www.hort.purdue.edu/newcrop/ncnu02/v5-267.html

 

David Smith, Singapore