Email to a friend
Hybrid grass may prove to
be valuable fuel source
photo to enlarge
by Kwame Ross
| Emily A. Heaton, a doctoral student of Stephen P.
Long, a professor of crop sciences and of plant biology,
stands next to one of three Miscanthus plots at the
intersection of South First Street and Airport Road
in Savoy. Giant Miscanthus, a hybrid grass that can
grow 13 feet high, drops its slender leaves in the
winter, leaving behind tall bamboo-like stems that
can be harvested in early spring and burned for fuel.
— Giant Miscanthus (Miscanthus x giganteus), a hybrid grass that
can grow 13 feet high, may be a valuable renewable fuel source for the
future, researchers at the University of Illinois at Urbana-Champaign
Stephen P. Long, a professor of crop
sciences and of plant
biology, recently took that message to Dublin, Ireland, where the
British Association for the Advancement of Science sponsored the annual
BA Festival of Science Sept. 3-10.
Closer to home, two of Long’s doctoral students, Emily A. Heaton
and Frank G. Dohleman, delivered their Miscanthus findings at the 49th
annual Agronomy Day, held on campus Aug. 18 and attended by more than
1,100 visitors from across the Midwest.
“Forty percent of U.S. energy is used as electricity,” Heaton
said. “The easiest way to get electricity is using a solid fuel
such as coal.”
Dry, leafless Miscanthus stems can be used as a solid fuel. The cool-weather-friendly
perennial grass, sometimes referred to as elephant grass or E-grass,
grows from an underground stem-like organ called a rhizome. Miscanthus,
a crop native to Asia and a relative of sugarcane, drops its slender
leaves in the winter, leaving behind tall bamboo-like stems that can
be harvested in early spring and burned for fuel.
Rhizomatous grasses such as Miscanthus are very clean fuels, said Dohleman,
who is studying for a doctorate in plant biology. Nutrients such as
nitrogen are transferred to the rhizome to be saved until the next growing
season, he said.
Burning Miscanthus produces only as much carbon dioxide as it removes
from the air as it grows, said Heaton, who is seeking a doctorate in
crop sciences. That balance means there is no net effect on atmospheric
carbon dioxide levels, which is not the case with fossil fuels, she
Miscanthus also is a very efficient fuel, because the energy ratio of
input to output is less than 0.2, Heaton said. In contrast, the ratios
exceed 0.8 for ethanol and biodiesel from canola, which are other plant-derived
Besides being a clean, efficient and renewable fuel source, Miscanthus
also is remarkably easy to grow. Upon reaching maturity, Miscanthus
has few needs as it outgrows weeds, requires little water and minimal
fertilizer and thrives in untilled fields, Heaton said. In untilled
fields, various wildlife species make their homes in the plant’s
leafy canopy and in the surrounding undisturbed soil.
Illinois researchers have found that Miscanthus grown in the state has
greater crop yields than in Europe, where it has been used commercially
for years, Long said. Full-grown plants produce 10-30 tons per acre
dry weight each year. Miscanthus yields in lowland areas around the
Alps, where the climate is similar to the Midwest, are at least 25 tons
per acre dry weight, wrote Heaton and colleagues in a paper published
in 2004 in the journal Mitigation and Adaptation Strategies for Global
Last year, Illinois researchers obtained 60 tons per hectare (2.47 acre),
Long said at the BA Festival of Science.
Using a computer simulator, Heaton predicted that if just 10 percent
of Illinois land mass was devoted to Miscanthus, it could provide 50
percent of Illinois electricity needs. Using Miscanthus for energy would
not necessarily reduce energy costs in the short term, Heaton said,
but there would be significant savings in carbon dioxide production.
The Illinois Miscanthus crop began three years ago when Heaton planted
400 Miscanthus rhizomes, which were generated from three rhizomes donated
by the Turfgrass Program in the department of natural resources and
environmental sciences. Because Miscanthus is sterile, cuttings of Miscanthus
rhizomes must be used to create new plants.
Now in their third year, the three 33-by-33 feet Miscanthus plots at
the intersection of South First Street and Airport Road in Savoy, Ill.,
are considered mature. Their 10-foot tall stems are twice as high as
switchgrass, a prairie grass native to Illinois. Grown side by side,
Miscanthus produces more than twice as much biomass as switchgrass,
To investigate how Miscanthus is so productive, Dohleman and others
take measurements of photosynthesis throughout the day. He measures
the intensity of the sun and then places a leaf in a chamber, allowing
him to measure the rate of photosynthesis depending upon ambient sunlight.
Preliminary results show that Miscanthus has a 27 percent greater rate
of photosynthesis at midday compared with switchgrass.
Nine different fields across the state are being used to help estimate
Miscanthus productivity, Heaton said. Plots in Champaign and Christian
counties each have more than 2 acres of Miscanthus, and DeKalb, Pike,
Pope, Wayne, Fayette and Mason counties have smaller plots. Plots in
Champaign County have shown the greatest yearly yields, according to
Long’s 2004 progress report to the Illinois Council on Food and
Agricultural Research, which funded the experiments.
“It is my hope that Illinois will take the lead in renewable energy
and that the state will benefit from that lead,” Long said.
Other varieties of Miscanthus have been grown successfully in Indiana,
Michigan and Ohio. However, the giant Miscanthus being grown by the
Illinois researchers has the greatest potential as a fuel source because
of its high yields and because it is sterile and cannot become a weed,
Heaton said. “Miscanthus sacchariflorus and some of the other
fertile Miscanthus species can be quite invasive,” she said.
At a research station near Hornum, Denmark, giant Miscanthus has been
grown for 22 years in Europe’s longest-running experimental field.
The crop has never been invasive and rhizome spread has been no more
than 1.5 meters (4.92 feet), said Uffe Jorgensen, senior scientist for
the Danish Institute of Agricultural Sciences.
The next step, Long said, is to demonstrate how Miscanthus goes from
a plant to a power source. Existing U.S. power plants could be modified
to use Miscanthus for fuel as in Europe, he said.
Long collaborates with researchers at the Institute of Genomic Biology
to study whether Miscanthus could be converted to alcohol, which could
be used as fuel.