Exploring Cellulosic Feedstock Options

Producing ethanol from a type of feedstock common in one region of the U.S. may not be feasible in another region. EPM investigates feedstock options currently available and in development in five portions of the U.S.
By Anna Austin | November 11, 2009
Long before commercial production of corn-based ethanol, it was known that growing corn isn't effective or even possible in all regions of the country. Furthermore, transporting corn long distances to ethanol plant locations is not economical. Thanks to emerging second-generation technologies and advancements in agriculture and plant science, however, more alternative feedstock options will soon make ethanol production possible areas of the U.S where it was previously not feasible.

For several years, groups at the U.S. EPA and the U.S. DOE's National Renewable Energy Laboratory have been working on tools to accurately recognize and quantify which types of feedstocks are plentiful, available, or have growth potential in particular regions of the country. Recently, the EPA and NREL released a Web-based, interactive geospatial application that allows users to view quantities of biomass resources in a specified area within the U.S.—including residues from crops, forests, and primary and secondary mills and urban wood waste, among others. This doesn't account for feedstock already spoken for or being utilized, so further assessments would be needed for any new venture or feedstock transitions. It does, however, give users an idea of what kinds of feedstocks are plentiful in a specific region of the U.S.

Additionally, the EPA has released a state-by-state assessment for cellulosic biomass resources, which estimates the current cellulosic biomass available in dry tons in each state, and also predicts what each state's cellulosic ethanol production could be by 2012.

Universities are developing or improving strains of biomass from switchgrass, miscanthus and alfalfa. Others are testing how the crops will grow in certain regions of the U.S. as well as how their yields and overall potential as a biofuel feedstock can be improved. In 2009, the USDA selected seven projects to receive a collective $6.3 million for biomass genomics research, five of which were universities.
Although corn is the old reliable in the Midwest, crop residue and perennial grasses such as switchgrass are making headway as cellulosic ethanol feedstock forerunners.

Perennial grasses/ crop residue

Switchgrass is a fast-growing, highly adaptable perennial grass that can easily be grown on marginal cropland, which is abundant in the Midwest, and much research is being done to maximize its performance and yields. So far, lowland varieties have the highest yields, but are more susceptible to cold injury in the northern U.S.

The USDA-Agriculture Research Service in Lincoln, Neb., is funding research focused on winter survival in switchgrass populations and individual plants specifically selected for greater yields, which will involve studying molecular events occurring in the crowns and rhizomes during two growing seasons and winters.

Project investigator Guatam Sarath says research is scheduled to begin next spring. "We've established some fields for this specific work, but actual data collection won't start until green-up next year," Sarath says.

A 10-year study in North Dakota aims to determine what types of grasses can sustain the state's soil and climate conditions and yield the most biomass, and to evaluate production, carbon sequestration, economics and longevity of perennial forages in western and central North Dakota.

Entities involved in the project include the North Dakota State University Central Grasslands Resource Extension Center, the North Dakota Game and Fish Department, and the state's commerce department and Department of Agribusiness and Applied Economics. Researchers hope that by increasing yields and harvesting biannually, growing the grasses will become an economical option.
Being the nation's agriculture belt, it isn't surprising that a recent study by the NREL found that when taking into account crop residue left for soil protection and animal feed and bedding, there is close to 600,000 dry tons of crop residues available for other uses on an annual basis just in Iowa, Minnesota and Illinois.

Many projects are still investigating the effects of utilizing crop residue for fuel applications. In September, Iowa State University officially dedicated a combination farm and bioprocessing facility to research the production of biomass and bioproducts. Research will include feedstock production; harvesting, transportation and storage of feedstocks; and land use changes arising from harvesting corn stover and other residues.

Wood residues/woody biomass

Many projects in the Southeast plan to utilize fast-growing woody biomass, which is highly abundant and accessible in that region partially because of its long-distance transportation costs. According to NREL, transporting forest-derived biomass can cost between 20 cents and 60 cents per dry ton per mile.

According to the Georgia Forestry Association, Georgia has 23.8 million acres of commercial forest land, more than any other state. Cellulosic ethanol developer Range Fuels Inc. will bring its first commercial-scale facility online next year in Soperton, Ga., and will utilize wood waste and residue from nearby timber operations. Patrick Wright, competitive analysis director of Range Fuels, says phase one of the Soperton plant is scheduled to begin production in the second quarter of 2010, running at a rate of less than 10 MMgy of cellulosic biofuels annually.

Another company planning a wood-to-ethanol project in the Southeast is Coskata Inc., although it's semi-commercial scale cellulosic ethanol plant is located near Madison, Pa. An exact location for the plant hasn't been disclosed, but Coskata CEO Bill Roe says the Southeast region has been selected because it is rich with woody biomass, much of which is available due to downturns in the housing and pulp and paper market markets.

Besides wood-derived biomass, perennial grasses such as switchgrass and miscanthus are also promising feedstock options for the Southeast, says Anelia Milbrandt, NREL senior resource analyst, and developer of the EPA/NREL biopower mapping application.

Wood residues/fast-growing woody biomass

A report by the Coalition of Northeastern Governors Policy Research Center Inc. indicated that the 11 states in the Northeast could produce 2.73 billion gallons of ethanol per year using available cellulosic feedstocks, namely wood waste, mill residues and corn stover.

Wood residues/woody biomass is in high abundance, especially in Pennsylvania, which boasts 17 million acres of forestland. The Northeast Regional Biomass Program estimates that more than 7 million tons of forest residues are available annually as a biomass resource, and more than 5 million tons of primary mill waste.

Though no commercial-scale cellulosic ethanol projects are planned for the region, a few semi-commercial or demonstration scale plants are in the works or are completed — including Coskata's, and Mascoma Corp.'s facility in Rome, N.Y., both of which utilize wood chips as a feedstock.

Though woody biomass is plentiful in the region, some groups are concerned with proper harvesting of the material, including Pennsylvania's Department of Conservation and Natural Resources, which last year released a 50-page document containing guidelines for harvesting woody biomass for alternative energy sources.

Willow and poplar trees, which grow faster than other trees and grow well in cold-weather states, are also promising cellulosic feedstock options in the Northeast, according to Mildbrandt.

Algae/municipal solid waste

The Southwest is certainly viewed as a place to grow algae, though generally speaking, all southern states (with warmer, wetter climates) are suitable for algae farming, Milbrandt says.

Utah-based Genifuel, which is partnered with the DOE's Pacific Northwest National Laboratory, is working toward growing aquatic biomass in what the company has labeled Genifarms, or outdoor ponds. CEO Jim Oyler says Genifuel's aquatic species can grow anywhere, in any climate, but to achieve the best and cheapest growth, consideration of cost-related economics is critical when choosing where to grow the biomass. "You'd actually like a warm, humid climate with relatively easy access to water supplies, so it probably is not optimum to grow aquatic biomass in the Northern U.S. or Canada; it's more optimum in the Southern U.S.," he says.

BlueFire Ethanol Inc. project is taking advantage of one of California's largest biomass resources—municipal solid waste—through a DOE-funded project in Lancaster.
The company has completed a 20-month licensing process and is currently awaiting the final financing needed to break ground on its fully permitted facility, which will use post-sorted cellulosic wastes diverted from southern California landfills to produce approximately 3.9 MMgy of ethanol.

According to the DOE, there are currently hundreds of landfills in the Southwest without renewable energy projects.

Fast-growing woody biomass/wood residuals

Fast-growing woody biomass, particularly hybrid poplar trees, is a focus in the Northwest. Poplar's quick water transpiration rates make the rainy Northwest an ideal place to grow plantations, especially in Washington and Oregon. The Oregon Department of Energy says there are more than 34,000 acres of hybrid poplar trees growing on plantations in Oregon. According to research performed at Washington State University, a 950-acre poplar field could yield 1 million gallons of ethanol per year.

Colorado-based Zeachem is currently constructing a DOE-funded 1.5 MMgy cellulosic ethanol demonstration facility in Boardman, Ore., using poplar trees and wood chips as a feedstock. The company has an agreement with GreenWood Resources, which operates a 23,000-acre poplar tree farm near Boardman, for the supply of poplar feedstock.

Woody biomass/residuals are also an attractive option in the Northwest. The DOE estimates about 9.8 million dry tons of woody biomass is available annually in Oregon alone. According to a Washington State University study, Washington has an annual production of more than 18 million tons of underutilized wood waste biomass.

Feedstock Forecast
"It's hard to say what the ‘big' ethanol feedstock will be," Milbrandt says. "At a national level, crop residues have been dominant over the last 10 years and are expected to hold their place. Regionally, I expect them to continue to be the main feedstock in the Midwest over the next 5 to10 years, with perennial grasses/fast growing woody crops coming online during that period."

Milbrandt says she expects wood residues (forest and primary mill) to continue to be the primary biomass sources in the Northwest, Northeast and Southeast over the next 5-10 years, combining with fast growing woody crops coming online in the Northwest and Northeast and a mixture of perennial grasses and fast-growing woody crops in the Southeast. "Generally, I expect crop and wood residues to continue to be the main cellulosic ethanol feedstock in the near future, and dedicated energy crops and algae developing in a long term," she says.

Regarding the hurdles in developing regional cellulosic biomass markets, Milbrandt says reliability of feedstock supply and lack of policy drivers will be among the main challenges. EP

Anna Austin is an associate editor at BBI International. Reach her at (701) 738-4968 or aaustin@bbiinternational.com.