By Bob Secter
CHILLICOTHE, IA — If there were such a thing as a Comeback Plant of the Year award–maybe Comeback of the Century–a top contender would have to be switchgrass, a dominant part of the tallgrass prairie that once blanketed much of North America.
That vast sea of grasses, so thick and high that pioneers said it could swallow a rider on horseback, all but disappeared as sodbusters ripped it away to make room for lush and productive cropland.
What was an obstacle to progress 150 years ago suddenly is getting a fresh, hard look as a major source of fuel. Our energy-starved nation is scrambling to come up with alternatives to limited supplies of expensive oil and natural gas, and there’s a growing buzz about switchgrass even though most Americans would need a botanical guide to identify it.
Agribusiness giant Archer Daniels Midland Co., the world’s largest producer of ethanol made from corn, this month unveiled plans to ramp up research into switchgrass as another source to make ethanol and other biofuels for cars, homes and industry. In Washington, the Democrats soon to take over as heads of the House and Senate Agriculture Committees have put development of switchgrass as a fuel source high on their priority list.
This is a “natural evolution of an industry that could be massive,” said Patricia Woertz, chief executive of Decatur, Ill.-based ADM.
Also known as tall panic grass, switchgrass doesn’t look much like the grasses that cover today’s lawns. It is a lanky plant, with stems up to 8 or 9 ft. high and a root system just as deep, topped with lacy seed-bearing panicles. It grows in thick, jungle-like tangles.
It also is especially good at storing energy from the sun. “A living solar battery” is what Canadian switchgrass researcher Roger Samson calls it.
The U.S. Agriculture Department calls switchgrass “perhaps our most valuable native grass.” Oak Ridge National Laboratory has identified it as the model plant species for fuel, better than corn, which is all the rage now as the prime ingredient of ethanol. President Bush highlighted the energy potential of switch grass in his State of the Union address this year.
So, like a once-treasured toy rediscovered after years in the attic, switchgrass is now the focus of talk about its revival–this time as a cash crop–on tens of millions of acres in the Midwest, South and Great Plains.
“This could very well be the future,” said Stephen Gardner, one of dozens of southeastern Iowa farmers who for years have supplied switchgrass for an electric generating experiment in Chillicothe that has shown encouraging results.
The notion of converting vegetation into fuel may seem odd in a nation that runs on oil, gas and coal. But fossil fuels themselves are the detritus of ancient plants, buried in the earth for millions of years.
They are also a finite resource, while fuel crops can be grown again and again. “Nature figured out long ago how to store chemical energy in plants,” explained Robert Brown, director of the office of biorenewable programs at Iowa State University.
University of Illinois Research
Energy can be squeezed from most any plant, and there are a lot of them under study these days as potential fuel sources. The University of Illinois at Urbana-Champaign is leading the way in research on giant miscanthus, a grass native to Asia. It can grow to 13 ft. with bamboo-like stems ripe for burning.
The trick today is to target the plants that can be most efficiently grown and tapped for fuel. For now, the renewable fuel of choice in the U.S. is corn-based ethanol. It is essentially alcohol made from the starches in grain. Humans have been fermenting and drinking it since prehistoric times.
Corn is abundant, and it has a clout-heavy lobby of farmers and agribusiness promoting it for ethanol, which is largely blended with gasoline. But corn has limitations as a raw material for fuel. Divert a lot of corn to ethanol production and food prices are bound to rise. Corn also is a resource hog, requiring good soil and lots of water, fertilizer and herbicide, heightening environmental concerns.
One prominent researcher contends it takes more fossil energy to grow and transform cornstarch into ethanol than the new fuel can yield, suggesting the process is a waste. Other experts disagree, but if there is an energy benefit to making ethanol this way, it is not huge.
The hope for switchgrass is that it may bypass a lot of those problems while providing more bang for the energy buck in an ecologically friendly and low-maintenance way.
The explanation hearkens back to the prairies of old. Near-treeless vistas of undulating grass once stretched from the Gulf of Mexico up into Canada, providing a feasting ground for birds and other wildlife and packing the soils with nutrients. The grasses once covered 60 percent of what is now Illinois, which calls itself the Prairie State.
Ironically, the fertile soil of the prairie also was its undoing. The farmers who eventually chopped it away liked to boast that the prairie topsoil was so deep and rich that it could grease the axles of their wagons.
There were lots of different grasses in the Midwest prairie, but switchgrass was one of the three predominant varieties. It didn’t need much water, it adapted to a wide range of latitudes and soils, and it sucked in a lot of carbon dioxide from the air as fuel to grow on.
Prairie fires burned so hot that they would create their own cyclones, a testament to the energy that the grasses stored away.
Those are some of the traits that are kindling interest in switchgrass as the nation scrambles to grow its way into energy self-sufficiency. David Bransby, a grasslands expert at Auburn University in Alabama, suggests a few more.
And It Grows Prodigiously
Bransby, who has studied switchgrass for 20 years, says the plant grows prodigiously, yielding huge per-acre amounts of what the energy industry calls biomass–a term for living material that can be turned into fuel.
Switchgrass requires no herbicides and little fertilizer, it can take hold on poor-quality land not suitable for most crops, and it is a perennial, meaning it doesn’t have to be replanted like corn after each harvest. Stands of good-quality switchgrass can last 10 years or more.
Switchgrass also has ecological benefits, Bransby said. Its deep roots bind soil and block erosion. They also pump a lot of carbon into the ground, essentially recycling carbon-based greenhouse gases emitted when the plant is burned as fuel.
“If we really put our minds to it, we can use this to help replace the oil we import from the Middle East very easily in the next 20 years,” Bransby said.
Unlike with corn, a cost-effective process to convert switchgrass and other fibrous plant material into ethanol hasn’t been perfected, though researchers say they’re close. ADM’s Woertz said biofuel producers right now are in a “chicken and egg” situation as they explore the potential of switchgrass.
“How do you build massive facilities when you haven’t grown the stuff yet, and then how do you grow the stuff if you haven’t anywhere to process it?” she asked.
Some experts argue that switchgrass would be an even better option as an ingredient for fuels other than ethanol, and the technology to make them exists now.
Samson, who runs a non-profit agricultural research institute in Quebec, said switchgrass already is being used to make a low-quality natural gas substitute suitable for heating farm structures and small industrial buildings. Such biogas systems are in wide use in Germany and China, he said.
Switchgrass also can be easily chopped and pressed into fuel pellets for burning in special furnaces to heat homes, Samson said. The slow-burning pellets heat for a price far less than natural gas, quickly paying for the cost of new heating equipment, he said.
“We think we’re heading toward an agrarian industrial revolution,” Samson predicted.
In Iowa, Gardner and more than 100 other growers have supplied switchgrass for years to a federally sanctioned experiment that burns the grass alongside coal in a power plant in tiny Chillicothe, 80 miles southeast of Des Moines. Preliminary results indicate that switchgrass burns almost as hot as the coal, and its presence in the fuel mix reduces sulfur dioxide and carbon dioxide emissions.
The Iowa farmers reaped their switchgrass from stands they had planted as part of the federal conservation reserve program, which pays farmers to take erosion-prone, low-quality cropland out of production.
Around the country, there are 36 million acres enrolled in the program, an area that if stitched together would cover every square inch of Illinois. Some already is planted in switch grass to help with erosion control.
In the prairies of old, nature mixed in switchgrass with other plant varieties that kept each other in check. That wouldn’t be the case if it is reintroduced as a fuel crop across wide stretches of the nation, and the prospect is troubling to some experts in invasive species.
Writing recently in the journal Science, a team of researchers led by S. Raghu of the Illinois Natural History Survey warned that wholesale plantings of switchgrass, miscanthus or other grasses grown for fuel could have an ecological downside.
The grasses are attracting interest as biofuel crops because they grow rapidly, need little water and appear resistant to most pests and diseases. But those are also traits that help invasive species wreak havoc on ecosystems and agriculture.
The U.S. spends more than $100 billion annually trying to beat back the ravages of invasive species such as kudzu, so Raghu and his colleagues urged caution as the pressure to develop new crops for fuel intensifies.