More Sustainable Feedstock for Ethanol

A six-year Great Lakes Bioenergy Research Center (GLBRC) study on the viability of different bioenergy feedstocks recently demonstrated that perennial cropping systems such as switchgrass, giant miscanthus, poplar, native grasses and prairie can yield as much biomass as corn stover.

The study is significant for addressing one of the biofuel industry’s biggest questions: Can environmentally beneficial crops produce enough biomass to make their conversion to ethanol efficient and economical?

Since 2008, research scientists Gregg Sanford and Gary Oates, based in the lab of CALS agronomy professor Randy Jackson, have worked with colleagues at Michigan State University (MSU) to cultivate more than 80 acres of crops with the potential to become feedstocks for so-called “second-generation” biofuels, that is, biofuels derived from non-food crops or the nonfood portion of plants. They’ve grown these crops at the CALS-based Arlington Agricultural Research Station and at MSU’s Kellogg Biological Station.

“We understand annual systems really well, but little research has been done on the yield of perennial cropping systems as they get established and begin to produce, or after farmland has been converted to a perennial system,” says Oates.

To find out basic information about how well certain crops produce biomass, Sanford and Oates tested the crops across two criteria: diversity of species, and whether a crop grows perennially (continuously, year after year) or annually (needing to be replanted each year).

Highly productive corn stover has thus far been the main feedstock for second-generation biofuels. And yet perennial cropping systems, which are better equipped to build soil quality, reduce runoff, and minimize greenhouse gas release into the atmosphere, confer more environmental benefits.

Corn, when grain is included, proved to be most productive over the first six-year period of the study at the Wisconsin site, but giant miscanthus, switchgrass, poplar and native grasses were not far behind. At the MSU site, where soil is less fertile, miscanthus actually produced the same amount of biomass as corn (grain included) in the experiment, with poplar and switchgrass within range.

“All of this means that, at large scales and on various soils, these crops are competitive with corn, the current dominant feedstock for ethanol,” Sanford says.

Now in the midst of the study’s eighth year, Sanford says the study will continue for the foreseeable future.

“We know that perennial systems can prevent negative impacts such as soil erosion and nitrate leaching, and that they also provide habitat for native species that provide beneficial ecosystem services,” Sanford says. “But there are still a lot of questions we want to answer about soil processes and properties— questions that take many years to answer.”

Researcher Gregg Sanford stands before a plot of giant miscanthus at Arlington.

Photo credit – Matthew Wisniewski

Sustainable by Design

THE CHILDREN’S SONG URGES HER TO FLY AWAY HOME, but the ladybug—or ladybeetle, as she’s properly called—is anything but a homebody. After feasting all summer on soybean aphids and other crop pests, the beetles take off from farm fields in search of snug overwintering spots, often winding up in people’s houses. Around Madison, this usually means a journey of five miles or more, says CALS entomology professor Claudio Gratton. But the insects can also fly much farther. In the Southwest, for example, they congregate on mountaintops. “You’ll come upon a bush just dripping with ladybeetles, and you know they probably had to travel 30 miles to get there,” says Tim Meehan, a research scientist working with Gratton who earned his doctorate in
New Mexico.

Those wandering ways got Gratton and Meehan wondering a few years back if the beetles’ lives were touched not just by the soybean fields where they fed, but by the wider world as well. They soon discovered that, indeed, “What the landscape looks like actually makes a big difference,” says Gratton. In experiments across the Midwest, ladybeetles devoured more aphids in fields nestled within a patchwork of woods and grassy pastures than in those surrounded by soybeans and corn as far as a bug’s eye could see.

Although the two still aren’t sure why this is, it led them to ponder another possibility that has big implications for the sustainability of our farmlands. If the chance variation that exists in some farming areas already gives ladybeetles a boost, what if farmlands were purposely designed for diversity? Would the insects dispatch even more aphids? Might they even become tiny tools of sustainability, allowing farmers to spray fewer chemicals?

It takes a lot of imagination to picture such a landscape today, with two-thirds of the Midwest’s cropland blanketed in corn and soybeans. But there is a force that could re-stitch the Corn Belt into a crazy quilt—the push toward ethanol and other types of bioenergy. True, the ethanol blended into gasoline today still comes exclusively from corn kernels. And few “dedicated” bioenergy crops, such as grasses, have been sown so far for making cellulosic ethanol from stalks and stems, or burning in power plants instead of coal.

But bioenergy crops will almost certainly grow widely one day. The goal of the U.S. Department of Energy (DOE) is to replace 30 percent of gasoline and other U.S. transportation fuels with biofuels by 2030. And that, CALS scientists say, offers a chance to reshape our farmlands in an unprecedented way, so they yield not only food and fuel, but also things like ladybeetles and the benefits they provide.

In scientific parlance those benefits are called “ecosystem services”—natural processes we rely on but don’t usually pay for, Meehan says. Pest control by ladybeetles is one service; pollination by native bees, water cleansing, soil formation and even aesthetic beauty are others. Today’s simplified agricultural landscapes excel at producing corn, cotton and other vital commodities in massive amounts, but these may come at the price of water quality, erosion, loss of bird and insect habitat and increased pesticide use, as another study by Meehan and Gratton recently found. The question now is whether switchgrass, willow and other biofuel crops could cut those costs by sowing some plant diversity back into the system.

“The focus now is land use, not just food or fuel or a new crop. How do we use land sustainably?” says Chris Kucharik, a CALS professor of agronomy and environmental studies. “It just so happens that fuel has ignited the debate over sustainable land use right now.”

At the same time, strong forces are working to maintain the status quo. Skyrocketing commodity prices and rising demand for ethanol have led many farmers to put as much land in corn as possible. This year, 92.3 million acres were planted, according to the U.S. Department of Agriculture, four million above last year’s total and the second highest amount since World War II.

Discovery Under Way

What will be the next oil?

That’s a frequent question raised about the future of energy—and not a surprising one considering the dominant role that that single fuel source has played in filling our energy needs.

While we still are searching for the answers to our energy future, one thing seems clear—there probably won’t be one next big thing, one dominant fuel source that will take the place of oil.

Which brings me to the topic of this issue: bioenergy. In 2007 CALS was awarded an initial $125 million from DOE—the largest federal grant ever received by CALS—to come up with new ways of drawing energy from plants. And so we embarked on a scientific endeavor that ranks as one of humankind’s biggest when we consider what we might gain: more ways to free ourselves from dependency on fossil fuels.

The discoveries emerging from these efforts are likely to benefit farmers, businesses and the overall economy in the entire state and region.

While some may have hoped that by this point we’d be tanking up with cellulosic ethanol, anyone familiar with the challenges recognized that after three and a half years, we’d just be warming up.

In fact, we’ve done that and more. As the stories in this issue show—and as an illustration on page 20 offers at a glance—Tim Donohue and his colleagues at the Great Lakes Bioenergy Research Center (GLBRC) have built a research pipeline that already has produced some promising discoveries and is poised to deliver more.

Hundreds of scientists are blazing trails in everything from sustainability—learning how biofuels will affect the environment in the long run—to fundamental research about cell wall growth and interactions with microbes. The GLBRC has strengthened connections with institutions across campus—for example, with the College of Engineering, where researchers are engine-testing biofuels—and across Lake Michigan, working in close cooperation with our partners at Michigan State University. Beyond college campuses, the discoveries emerging from these efforts are likely to benefit farmers, businesses and the overall economy in the entire state and region.

We do not yet know the exact role biofuel will play in the mix of renewable sources that will comprise our energy future. Time and more discovery will tell. We do know that the GLBRC is off to a promising start.

Where Are We Now?

TIM DONOHUE HAS SPENT THE LAST FOUR YEARS BUILDING A PIPELINE—but not the kind that springs to mind when we think of fuel.

The professor of bacteriology heads the CALS-led Great Lakes Bioenergy Research Center (GLBRC), founded with $142 million from the U.S. Department of Energy and a groundbreaking charge—to create the next generation of biofuels by harnessing renewable energy from the nonfood plants that are so plentiful all around us: grasses, trees and crop residues.

“We need to create liquid transportation fuels that are more cost-effective, more sustainable and won’t compromise the Earth or our quality of life,” says Donohue. “We’re in the middle of developing ways to generate these new fuels that are essential for powering our daily lives.”

With Michigan State University (MSU) as UW–Madison’s major partner, Donohue has assembled a team that now includes more than 400 researchers and staff and an additional nine member institutions. The effort spans two countries, 11 states and more than 60 individual lab and field facilities.

That’s a lot of brainpower. But the magnitude of the effort is commensurate with the task at hand, Donohue notes.

“We need to be considering everything from roots in the ground to what’s coming out of the nozzle,” Donohue says. “Without such a holistic approach, we won’t be able to demonstrate that this technology is feasible or see the weak spots where we can make improvements.”

What GLBRC has built is a research pipeline, a process that considers all factors that go into developing and implementing cellulosic biofuels—from creating sustainable agricultural landscapes and building better bioenergy crops to innovations in plant biomass processing and converting plant sugars into fuels.

While the promise of creating sustainable plant-based fuels isn’t new, the level of public investment needed to tackle this challenge has only recently emerged. According to the International Energy Agency, the United States leads world spending on biofuels public research, development and demonstration projects, investing $189 million in 2010 alone.

“By relying on fossils fuels, we’re living on energy that arrived on Earth many millions of years ago,” says Steve Slater, GLBRC’s scientific programs manager. “In order to reach a sustainable energy economy, we need to learn to live on the energy that arrives from the sun today. There’s a lot of that solar energy held within plant biomass, if we can figure out how to sustainably convert it to liquid fuels.”

Four years into its five-year grant, GLBRC has made some significant breakthroughs along the research pipeline. Here are some major points of interest.

First Stop: PLANTS

At agricultural research stations in Wisconsin and Michigan, GLBRC researchers tend to tall stands of such biofuel crops as switchgrass and miscanthus, measuring above-ground traits like crop yield and digging down in the dirt to monitor soil microbes and water movement. Sophisticated instruments measure greenhouse gases such as carbon dioxide and nitrous oxide. Researchers count birds and insects to measure biodiversity and use satellite data to capture a watershed-level view of land use patterns.

It’s a lot of information, but each measurement plays a role in determining how these crop contenders would fare as large-scale bioenergy crops.

The leaves and stalks of these potential bioenergy plants are comprised of large quantities of cellulose, the most abundant organic compound on the planet. Cellulose is a polysaccharide, a long chain of tightly linked sugar subunits that must be broken down into simple sugars before they can be processed into biofuel. That alone is difficult—but to make the process even harder, much of a plant’s cellulose is locked within cell walls that form a tough, protective barrier. Breaking past the walls, using enzymes or chemicals to do so, is one of the biggest challenges in creating economically viable cellulosic biofuels.

Plant cell wall structures have evolved over time to fight off pests and disease. The more scientists understand about how the walls are created, the easier it will be to break them apart. DNA sequencing capacity provided by the Department of Energy (DOE) Joint Genome Institute allows plant breeders access to genetic and genomic data that provide clues about how those cell wall layers are built.

While determining the best genetic traits for bioenergy crops is a long-range goal, GLBRC plant researchers already have made important headway when it comes to tackling lignin, one of the toughest compounds that make up plant cell walls. Researchers hope to take it apart to get at the cellulose locked inside and convert small pieces of lignin into valuable co-products. CALS biochemistry professor John Ralph and his team have identified a gene that would allow easily breakable bonds to be incorporated into plant cell walls. They’re calling this new technology Zip-Lignin™ for its ability to break apart—or unzip—the lignin within. By getting lignin out of the way, biomass processing could be completed at lower temperatures. And lower temperatures mean lower overall costs.

And on another track, GLBRC researchers at MSU have located an enzyme that creates a plant oil with unique biodiesel-like properties. Now they’re working to encourage plants to produce more of that oil, which could be used directly as a “drop-in” or ready-to-use diesel replacement.

Beyond the Gas Tank

ON TIM BAYE’S LIST OF WISCONSIN BIOMASS-BASED PRODUCTS, LIPSTICK looms larger than ethanol.

“One of the most attractive markets this year is a paraffin derivative for lipstick use made from bio-based materials,”
says Baye, a UW–Extension professor of business development who specializes in bioenergy consulting and executive
education.

“The bio-based chemical market is appealing because you get a better return on a more modest amount of feedstock compared to fuels,” he says. “The markets are not as volatile as they are for liquid fuels, and we don’t need major infrastructure, such as pipelines, to move the stuff. We can do it by truck and train.”

Baye has been crunching numbers on bioenergy projects for 27 years, both in his current job and in several private sector positions, including a two-year stint leading an initiative to start up an ethanol plant. Since the mid-1990s he’s also been experimenting with growing biofuel crops—switchgrass, sorghum, aspen and mixed grass stands—on a 240-acre farm in Woodman.

Asked what he thinks Wisconsin will be doing with biomass in the future, he quickly ticks off a dozen projects that already are operating or are on the drawing boards. The tally includes electrical plants fueled by everything from old railroad ties to landfill waste to willow, paper mills that have branched into wood pellets and biodiesel, and municipalities making biogas and fertilizer
from wastewater.

Notably lower on his list: corn-based and cellulosic ethanol.

“We’ll continue to produce liquid fuels from biomass, including corn, as long as the margins are justifiable,” Baye says. “But we don’t have the long growing season they have down South and in the tropics. That’s where you have higher biomass growth rates and yields, and that’s where we’re likely to see most of the biomass-based liquid fuels produced.”

What he does expect to see are lots of multipurpose facilities, where firms supplement their core business with energy and other biomass-based products in order to diversify, cut costs, spur revenues and make use of industrial residues. He cites the paper industry as a prime example.

“A number of our paper plants are planning on bolting on technology platforms to allow them to produce products other than paper,” he says. “A pulp tree may still go to the paper plant, but be converted to something much different than paper.”

He points to a Wisconsin paper mill, Flambeau River Papers, and its planned sister facility, Flambeau River BioFuels, as a national leader. Flambeau River Papers is refining its residual, pulp liquor—a rich red-brown broth left over from the paper-making process—into such value-added products as xylitol, used in making sugar-free gum, and into a binder used for dust control on dirt roads. The paper mill is powered by a biomass-fueled boiler. Flambeau River Biofuels plans on producing biodiesel and industrial lubricants and waxes in a facility scheduled to begin construction in 2012.

This strategy isn’t limited to paper plants. Corn-based ethanol plants are also considering adding processes to improve performance and diversify. Some of the first cellulosic ethanol plants have taken this approach and are eyeing the chemical market too.

Baye also expects to see more biogas digesters—producing methane and generating power and heat—coupled with municipal waste treatment plants to deal with wastewater and industrial residuals laden with organic content from food processors and other manufacturers.

“Municipalities are under pressure to upgrade these plants, which means higher charges,” Baye says. “To minimize these upgrades, they will look to divert the organic material and get a little gift back in the form of biogas. And there are a number of opportunities for them to produce additional, high value products—especially fertilizers.” New regulations addressing phosphorus management will likely accelerate this trend.

Baye says that many such projects will require partnerships between municipalities, local industries and farmers, who will grow switchgrass, sorghum and other bioenergy crops as additional feedstock for the digesters.

And even if Wisconsin doesn’t lead the pack in ethanol production, Baye thinks the Badger State will benefit from any growth in the ethanol industry. The expertise acquired making paper, beer, silage and cheese transfers nicely to the bioenergy business, and it’s a marketable product in and of itself, he points out.

“In the future we probably will be buying cellulosic fuel from other regions, but we’ll be selling them chemicals and enzymes and vats and pumps, technology, legal services and know-how,” Baye says.

Cash Crop Biomass

WISCONSIN FARMERS have been growing biomass for generations, says Kevin Shinners. They just have a different name for it.

“Biomass is really just poor-quality forage,” says the CALS agricultural engineer. “We allow it to get very mature and it’s really high in fiber, so it doesn’t make very good animal feed, but it
makes great biomass.”

And Wisconsin farmers have a leg up in the business of producing biomass, says Shinners, a specialist in forage systems who branched out into bioenergy crops about 10 years ago.

“We have all of the tools to harvest and handle and process it. And an added advantage is that when we take biomass off the field, we have new places to put our dairy manure,” he says. “When you take corn stover off the field, you’re
removing nutrients that you need for next year’s crop. A Wisconsin farmer can apply manure, while an Illinois farmer may have to go out and buy fertilizer.”

Wisconsin also is rich in off-farm resources. The state’s custom harvesters are expert at chopping stalks and grass, and biomass could fit nicely into their schedule. After they finish chopping corn silage in September, crews could move on to corn stover or switchgrass in October and November, spreading fixed costs over more acres and keeping employees working longer.

In fact, under some business models, farmers might job out most of their biomass crop production. If the crop is a perennial, such as switchgrass, the farmer may spend more time in front of the computer and on the phone than out in the field. “Once the crop is established, he’ll manage fertilization and weed control through an agronomic service, cutting and removal through a custom harvester and marketing through a biomass aggregator,” Shinners says.

But even though Wisconsin farmers may be very much at home with the types of crops involved and the mechanics of producing them, they’ll be on less familiar ground when it comes to marketing, Shinners notes.

“If you’re a cash crop farmer, you’re used to marketing your corn and beans through multiple paths, selling some out of the field, storing some, selling futures, to optimize what you earn on an annual basis,” he says. “For biomass, you’ll have to change your mindset.

“If a firm builds a large cellulosic biorefinery here, it will need an absolute dedicated supply,” Shinners says. “If half the people in the area decided not to produce biomass one year, that plant would be a dinosaur.” Meaning that a critical mass of local farmers must be willing to lock into a long-term production contract.

The economics of biomass are driven by the fact that, pound for pound, the stuff isn’t worth as much as other crops. Profit margins may be slim, so farmers will need to produce as efficiently as possible.

That’s where Shinners comes in. His research centers on streamlining the harvest and handling a variety of biomass crops, including such perennials as switchgrass and reed canarygrass, and annuals such as sorghum. But his biggest push has been in corn stover—the stalks and leaves and cobs left when the kernels are removed—simply because there’s so much of it.

“There are some 90 million acres of corn being grown in the United States this year, and with the prices we’re seeing, there’s going to be more and more of it grown. If you’re really interested in biomass, it’s right there at our doorstep,” he reasons.

Since profit-minded crop producers aim to make as few trips across the field as possible, Shinners’ first efforts focused on harvesting both corn grain and corn stover in one pass. Essentially, he grafted a forage harvester to the back of a combine and hitched a wagon behind to catch the chopped stover.

This impressive 50-foot train of machinery worked, he says, but handling two crops at the same time slowed down the grain harvest, putting both yield and quality at risk. “That’s even more of an issue these days, when we have seen corn go over $7 per bushel,” he says. “As corn grain increases in value, everything that slows the combine down has a much greater economic cost.”

Shinners is focusing now on a system in which the combine harvests grain and leaves the stover behind in a long, neat row. “A custom harvester could come in behind and chop these windrows and store them for the farmer.”

Since buyers will need year-round deliveries, storing biomass crop until it’s needed is part of the equation. Shinners thinks the best approach is one that dairy farmers use for forage—seal it from the air in long plastic bags or covered bunkers and let it ferment. “We know this from dairying: You can open up a silo bag from two years ago and it’s still good quality,” he says.

That fermented biomass could be good enough to eat—by livestock, at least—which may offer farmers a way to take advantage of the bioenergy market without having to wait for a biomass refinery to be built nearby.

“If we apply amendments like lime right before we store corn stover, the feed value can increase substantially,” says Shinners. “So instead of waiting for somebody to develop a biorefinery in Wisconsin to convert stover to ethanol, why not divert some of the grain normally used to feed cattle toward ethanol production and use the stover to replace the corn as animal feed?”