Switchgrass grown for biofuel production yields significantly more energy than is consumed in the production and conversion into cellulosic ethanol, says Ken Vogel, a USDA-ARS geneticist in the University of Nebraska-Lincoln (UNL) agronomy and horticulture department.
The prairie grass produced more than 500% additional energy than was needed to grow, harvest and process it into cellulosic ethanol. That's according to estimates made by Vogel and UNL researchers in a five-year study involving switchgrass fields on farms in Nebraska, North Dakota and South Dakota. It is the largest study to date examining net energy output, greenhouse gas emissions, biomass yields, ag inputs and estimated cellulosic ethanol production from switchgrass grown and managed for biomass fuel.
The joint USDA-ARS and UNL Institute of Agriculture and Natural Resources study also found greenhouse gas emissions from cellulosic ethanol made from switchgrass were 94% lower than estimated greenhouse gas emissions from gasoline production.
“This clearly demonstrates that switchgrass is not only energy-efficient, but can be used in a renewable biofuel economy to reduce reliance on fossil fuels, reduce greenhouse gas emissions and enhance rural economies,” says Vogel.
The research paper is available online at www.pnas.org/cgi.