Gumweed in Nevada could be used as jet fuel for the military

Glenn Miller working with gumweed at NAES Main Station Field Lab

Department of Natural Resources and Environmental Science’s Glenn Miller is leading the effort to convert roadside gumweed into biofuel, which could help contribute to fuel supplies for the military.

"The plant Grindelia squarosa, known as curly top gumweed, has extractable hydrocarbons with the potential use as a biodiesel or biomaterials crop," Miller said. "Gumweed is native in Nevada and grows on the side of freeways and, more importantly, is an arid land crop that requires less water than other substitutes like alfalfa. Alfalfa takes five feet of water to grow while gumweed uses no more than a foot of water."

The collaborators on the project planted the gumweed at both of UNR’s Agricultural Experiment Stations (Valley Road Field Lab and Main Station Field Lab) using minimal water and fertilizer resources. After growing and harvesting the gumweed, it went through biomass processing where it was broken down to liquid that smells like tar.

"We are looking at breaking it down because it uses less water and it's already acclimated to Nevada conditions," Miller said. "It would be beneficial generating this arid-land crop because it doesn't compete with food or animal feed. The primary resource for diesel fuel is soy beans and ethanol for corn which are always in direct competition with food."

The final biofuel product from the chemical engineering process can produce up to 122 gallons per acre on semi-arid lands of Nevada on a biennial basis. The crops would require minimum inputs of nutrients and water and have the potential to be converted into jet fuel, which has garnered the interest from the military - the largest fuel consumer in the United States.

Miller said the U.S. Navy is interested in using the biofuel as jet fuel. The project received $500,000 in grant funding from the USDA and has the potential to supply up to 20 percent of fuel demand for the military.

"It is estimated that if even 10 percent of sagebrush-covered lands in Nevada are used to grow gumweed for aviation biofuels, 400 to 600 million gallons per year of jet biofuels could be produced," Hongfei Lin, a collaborator from the College of Engineering, said. "That's definitely incredible. There's lots of potential."

Lin, a professor of chemical and materials engineering is working on the project with Miller to identify a catalyst that can be used to convert biomass into fuel using an unconventional approach to biofuel production. Instead of adding hydrogen to biomass, Lin is exploring a more cost-effective manner using an oxidation process.

The highly drought-tolerant and salt-tolerant crop can be harvested twice in its second year of growth, with the first harvest in July-August when the milky white, sticky buds turn into yellow flowers. The second harvest is in early October of the same year.
The project to develop drought-tolerant energy crops capable of surviving in Nevada's desert climate is a collaborative effort between CABNR and College of Engineering.

The research team includes Miller, David Shintani, associate dean and professor of biochemistry and molecular biology, and Lin and Chuck Coronella, both professors in Engineering.

"The efforts of Dr. Miller and his colleagues to develop new generation biofuels from gumweed and other Nevada plant species are well aligned with our efforts to establish CABNR and NAES as world leaders in sustainable dryland agriculture," said Bill Payne, CABNR’s dean. "Today's historically low oil prices cannot last indefinitely and will eventually once again rise due to policy, limited supply, or other factors. As prices once again reach $80 or more per barrel, this type of technology will look increasingly attractive to an industrial world."