The quest for renewable energy sources to one day replace or reduce fossil fuels is taking a new turn at the University of Maryland Eastern Shore. Research is in progress to see if several varieties of trees and other plants, such as switchgrass, can be grown, harvested economically and used as sustainable bioenergy feedstocks.
“Bioenergy is one future source of renewable energy, but there are a lot of variables that effect both the economics and the sustainability of biofeedstock sources,” said Dr. Jonathan Cumming (far left), chair of UMES’ Department of Natural Sciences. “We are investigating a diverse portfolio of feedstocks for their viability for this purpose. They require a lot of processing to yield energy-dense fuels, such as aviation fuel, but they provide many benefits.”
Bioenergy feedstocks help mitigate climate change and support ecosystem health, Cumming said. These plants absorb carbon dioxide, a greenhouse gas, and convert it into biomass through photosynthesis. Carbon from plant material is used as the source of carbon for fuel, rather than fossil sources like oil, but the plants use carbon dioxide from the atmosphere and also transfer organic carbon into the ground, enhancing the health of the soil.
“The big thing now with bioenergy is providing alternatives to fossil fuels without taking away from the food chain,” he said, referring to the current practice of producing ethanol from corn.
Cumming and fellow researchers associated with the Center for Bioenergy Innovation at the Oak Ridge National Laboratory in Tennessee are particularly exploring eastern cottonwood trees and nine genotypes of a poplar hybrid species altered genetically to deposit more carbon in the soil than is typical and to be more drought-resistant to withstand effects of climate change.
“The proof in the pudding is putting the right genetically modified tree in the right field,” Cumming said.
Over 200 of the trees in the U.S. Department of Energy-funded study were planted three years ago and last fall in a 1.5-acre plot at UMES’ Research, Extension and Teaching Farm. The trees are not irrigated and the field is monitored for climate conditions, such as temperature, rainfall, and salinity, among others.
“We are looking at what is happening both above and below ground to understand the patterns of carbon storage in the trees and carbon transfer to the soil that are helpful for the environment,” Cumming explained.
So far, he said, the eastern cottonwood and poplar trees are “getting really good growth” in the field test. Trees could be ready for harvest after three years, and the tree trunks would be ground and the lignin and cellulose extracted and used for feedstocks for biofuel production.
Supported by a Climate Smart grant from USDA-NRCS, Cumming is also working with partners, the University of Maryland and Chesapeake Utilities Corporation, on using switchgrass and other Maryland cover crops as alternative cellulosic feedstocks for biogas production from the anaerobic digestion of chicken litter. The anaerobic digestion process is a way of treating excess chicken litter, extract usable energy in the form of methane from it, and creating a nutrient stable end product for field application.
“The digestion process is much more efficient if we add plant material to the feedstock mix,” Cumming said. “Switchgrass can be grown under various conditions, has everything needed for carbon sequestration and ferments well for bioenergy feedstock production.” In addition, local winter cover crops can be harvested and used as well.
Under the USDA grant, UMES and its partners are seeking farmers interested in growing specific alternative crops that can add to their farm revenue stream while serving as test plant material for an anaerobic digestion process.
“Everything hinges on economics. It has to be profitable for farmers to grow,” Cumming emphasized. “Through this program, we are able to provide stipends and other funds to our partner farmers.” These farmers then become part of a renewable energy initiative on the Eastern Shore.
Visit www.acredelmarva.org for more information.
Gail Stephens, agricultural communications and media associate, University of Maryland Eastern Shore, School of Agricultural and Natural Sciences, UMES Extension, gcstephens@umes.edu., 410-621-3850.
Photo by Todd Dudek, agricultural communications, University of Maryland Eastern Shore, School of Agricultural and Natural Sciences, UMES Extension, tdudek@umes.edu.
