Wide range of plants offer cellulosic biofuel potential, ecological diversity

Aug 12, 2010

When it comes to selecting the right plant source for future cellulosic biofuel production, the solution won't be one-size-fits-all, and it certainly doesn't have to involve food and feed crops.

In a "Perspective" article in the Aug. 13 edition of the Journal Science, researchers from the Energy Biosciences Institute suggest that a diversity of plant species, adaptable to the climate and soil conditions of specific regions of the world, can be used to develop agroecosystems for that are compatible with contemporary environmental goals.

EBI Director Chris Somerville of the University of California, Berkeley, and Deputy Director Steve Long of the University of Illinois at Urbana-Champaign were co-authors with EBI bioenergy analysts Caroline Taylor, Heather Youngs and Sarah Davis. The institute is a research collaboration between UC Berkeley, the University of Illinois, Lawrence Berkeley National Laboratory, and the funding sponsor BP.

The article, "Feedstocks for Lignocellulosic Biofuels," discusses the sustainability of current and future crops that may be used to produce advanced biofuels with emerging technologies that use non-edible parts of plants. Such crops include perennial grasses like Miscanthus grown in the rain-fed areas of the U.S. Midwest, East and South; sugarcane in Brazil and other tropical regions, including the southeastern U.S.; Agave in semiarid regions such as Mexico and the U.S. Southwest; and woody biomass from various sources.

"The ability to produce lignocellulosic fuels sustainably is of paramount importance," the authors write. "Because the use of groundwater is generally not sustainable, we envision that the type of grown in a given region will be primarily related to water-use efficiency."

For example, Agave can grow in more arid regions, and since much of the land that has fallen out of agricultural production worldwide is semiarid, "it appears that the amount of land that may be available for cultivation of agave species is vast," the report says. About 18 percent of the earth's terrestrial surface is semiarid.

The article points out that biofuel feedstocks need not grow on land currently being farmed for food and animal feed. Some plants, like Miscanthus and switchgrass, have intrinsically high light, water and nitrogen use efficiency. Additionally, reduced tillage and perennial root systems add carbon to the soil and protect against erosion. Thus marginal or abandoned agricultural lands may be developed specifically as biofuel feedstock plantations without competing with food and feed.

According to the report, the government of Brazil has plans to intensify its cattle-grazing operations, making land available for agriculture without clearing natural ecosystems. With its highly developed sugarcane-based ethanol industry, Brazil alone could produce liquid fuels equivalent to about 14 percent of the current world transportation fuel demand by 2030.

In North America, wood is routinely harvested sustainably for lumber and paper, but activity has declined over the past several decades. As electronic media and paper recycling gain in popularity, the reduced demand for pulp woods could provide opportunities for large amounts of woody biomass to contribute to biofuel production, the authors state.

Even corn, the largest global source of grain and feed and a feedstock for ethanol, is given consideration by the authors, but not for its grain. The huge amounts of stems and stripped cobs (stover) of the corn plants have potential as cellulosic fuel sources. However, the report notes, "there is concern that removal of even half the stover would exacerbate loss of soil carbon and erosion and would also require additional inputs of fertilizer to replace lost minerals." Costs for harvesting and transport may also be prohibitive.

The diversity and geographic adaptability of crops available as potential feedstocks can be used to support ecosystem health throughout the world, the EBI researchers conclude. "By focusing on the use of dedicated energy crops - rather than on repurposing food and feed crops - it should be possible to overcome many of the problematic constraints associated with our narrow dependence on a relatively small number of food crops and to develop agroecosystems for fuel production that are compatible with contemporary environmental goals," they write.

They also encourage long-term research efforts focused on cellulosic biomass cropping systems in order to identify best management practices that maximize productivity and environmental benefits while meeting sustainability goals.

Explore further: Solar energy prices see double-digit declines in 2013, trend expected to continue

Related Stories

Sustainable biofuels from forests, grasslands and rangelands

Apr 28, 2010

The promise of switchgrass, the challenges for forests and the costs of corn-based ethanol production: Ecological scientists review the many factors surrounding biofuel crop production and its implications on ecosystem health ...

Energy crops impact environmental quality

Apr 04, 2010

Crop residues, perennial warm season grasses, and short-rotation woody crops are potential biomass sources for cellulosic ethanol production. While most research is focused on the conversion of cellulosic feeedstocks into ...

Beyond the corn field: Balancing fuel, food and biodiversity

Feb 16, 2010

The development of alternative fuel will greatly benefit the U.S., say scientists in an Energy Foundation-funded report published today by the Ecological Society of America (ESA), the nation's largest organization of ecological ...

Recommended for you

First-of-a-kind supercritical CO2 turbine

Oct 20, 2014

Toshiba Corporation today announced that it will supply a first-of-a-kind supercritical CO2 turbine to a demonstration plant being built in Texas, USA. The plant will be developed by NET Power, LLC, a U.S. venture, together w ...

Drive system saves space and weight in electric cars

Oct 17, 2014

Siemens has developed a solution for integrating an electric car's motor and inverter in a single housing. Until now, the motor and the inverter, which converts the battery's direct current into alternating ...

User comments : 1

Adjust slider to filter visible comments by rank

Display comments: newest first

jerryd
not rated yet Aug 14, 2010
Cellulosic ethanol is a scam. It has never been cost effective and probably never will. Far better just burn or gasify the biomass and turn it into any other HC by FT or other processes.