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Cellulosic Ethanol's Quest for Feedstocks and Collection Methods
by Jonathan Eisenthal

The Department of Energy has set the ambitious timeline – and officials won’t back away from it just yet – of delivering commercially viable cellulose-derived ethanol to the American transportation fuel market just three short years from now.

The rush is on.

Choosing feedstocks with an eye to logistics seems to be the first critical question.

Ethanol Today talked to a number of experts, some with views of the big picture, some working in their own biomass plots pursuing the kind of research that will make this happen.

One of the best broad views comes through the reports of U.S. Department of Energy feedstock specialist Sam Tagore. The presentation he made at the 2008 American Coalition for Ethanol conference can be found on Ethanol.org under the “Conference” heading.

Another invaluable resource is biomass energy veteran Jim Hettenhaus, an entrepreneur who came out of the enzyme industry and has worked on cellulose-to-energy solutions since the Clinton administration. He points to the Terrabon pilot plant that came online last month in Texas as the most apt model for cellulose ethanol in the Farm Belt. The system, created by a Texas A&M professor, could solve both the logistical nightmare of moving lots of loose organic material over long distances, while providing a model that can revive farmer and local ownership in energy production.

Various counts of active cellulose ethanol projects exist. In addition to Tagore’s report, Earth2Tech.com posted a survey at mid-year that counted 11 companies “racing” to build U.S. cellulosic ethanol plants.

The DOE selected six projects to fund in February 2007, and four of those remain active. Iogen’s wheat straw based project in Idaho has been shelved in favor of a project going forward in Canada, and ALICO, Inc.’s Florida-based project that would have utilized citrus and other ag waste, and eventually energy cane, has also dropped out of the DOE program.

In January, DOE announced another four competitively selected, cost-shared projects that would be commercial-scale cellulose ethanol plants: ICM, Inc. would build a facility in Missouri, NewPage would build a facility in Wisconsin, Pacific Ethanol has proposed a facility in Oregon, and Canadian-based Lignol Innovations would build in Colorado.

What is quickly becoming a maxim of the incipient cellulose ethanol industry is this quip from Professor Bruce Dale of Michigan State University, one of the nation’s experts on next generation energy development: “All biomass is local.”

That is, each region will present different soil, climate, and agronomic considerations that will render some sources of biomass better than others in that region. According to Tagore, the current assumption is that about half of the biomass for a cellulose ethanol industry would come from ag residues and herbaceous energy crops, while the remainder would come from forest biomass residues and other waste streams.

To pursue that question of feedstock selection and logistics, USDA, DOE, and the land grant universities of the Sun Grant Initiative have teamed up to create five Regional Biomass Feedstock partnerships. These groups are conducting numerous field trials on a variety of energy crops, each testing different cultivars of energy crops, evaluating the effects of residue removal from agricultural lands, and examining the efficiency of Conservation Reserve Program (CRP) lands.

This fall will present another critical influx of data to answer questions like which feedstock to grow where. But these trials may also raise more questions. The five regional groups are at Oregon State University, South Dakota State University, Oklahoma State University, University of Tennessee, and Cornell University.

DOE invited stakeholders, including private industry, to respond to a Request For Information regarding “Development of Supply Systems to Handle and Deliver High Volume Biomass Feedstocks for Cellulosic Biofuels production.” The agency tapped members all along the supply chain and asked questions such as what volume of feedstock would be optimal for a biomass refinery; what stages or processing are necessary along the way; if current ag equipment isn’t adequate, what would you add or modify; and how long would it take to demonstrate your ideal biomass supply chain?

“We would like to do some validation,” Tagore said. “We need to team up with growers, middlemen, truckers, and manufacturers, all the way to the end user – a biorefinery. We would like to get the private sector coming forward as a team. DOE plans to issue a Request For Proposals based on the answers to this RFI, we hope before the end of the year.”

POET looks to abundant, biomass-dense corn cobs

South Dakota-based POET works with thousands of Midwestern farmers who deliver grain to its 26 ethanol plants. The company wants to expand that relationship, and offer farmers a new market and another revenue stream, by buying farmers’ corn cobs for cellulosic ethanol production. Farmers would collect corn cobs and pile them at the edges of their fields.

“ In our model of a commodity-biomass market, the farmer’s responsibility ends at the edge of the field ,” said Jim Sturdevant, Director of Project LIBERTY, POET’s cellulose-to-ethanol project. “We need to make this as efficient and as affordable as possible to make it go.”

So POET or a third party would collect the cobs right from the edge of the field and pay the farmer somewhere between and per ton, according to Sturdevant.

POET will co-locate its cellulose-to-ethanol processing facility at its existing corn-to-ethanol plant in Emmetsburg, Iowa. The company would bring the new cellulose technology online sometime in mid- to late 2011.

The plant will utilize a minimum of 770 bone-dry tons of biomass per day – a combination of corn cobs and the fiber, derived from the corn kernels when specially milled and separated from the starch and oil in a process called fractionation. This would create a nameplate production of about 25 million gallons per year of cellulosic ethanol. Sturdevant said those cobs would come from approximately 275,000 acres of corn, which is possible to achieve within a 30-mile radius of the plant.

POET has managed to draw a range of companies, from CASE IH to small shop operators, in to the quest for appropriate equipment for the whole cob supply chain – from harvesting, collecting, piling, pile-management, transportation, to the at-plant grinding. On November 6, POET and equipment companies will host demonstrations of cob harvest equipment at a “Project LIBERTY Field Day” to be held on the grounds of the Emmetsburg plant.

“Why cobs? Because they are everywhere,” Sturdevant said. “Ethanol plants are surrounded by corn fields. Today cobs are part of the crop residue that lays on the field. Research shows that cobs contain just a small amount of the nutrients contained in the stover, so cobs can be removed without degrading soil fertility. In fact, taking the cobs and leaving the stover may actually benefit soil fertility for corn growth, according to early indications of some research. Also, cob density is higher than that of stover, making transportation more economical. In addition, using cobs as a feedstock for cellulosic ethanol does not require changes to cropping patterns or land use.”

In 2007 producers working with POET harvested and piled 4,000 acres of cobs in South Dakota. POET conducted numerous cob storage experiments, all with favorable results. This year the project expanded to sites in Texas and Iowa, as well.

Energy crops cultivated at commercial scale

Vance Owens, a professor of forage agronomy and the leader of the Regional Biomass Feedstock Group research at South Dakota State University, is working on trials of switchgrass, miscanthus, and other dedicated energy crops.

“We have selected a class of species, and we’re looking at switchgrass, energy cane, sorghum, miscanthus, and then CRP ground,” Owens said. “For each of these trials we have several locations.”

In order to create a closer approximation to the real commercial situation, the partnerships are working at a larger scale than typical university ag research.

“As part of the partnership, one thing was to scale it up,” Owens noted. “ We’re doing switchgrass and CRP tests on anywhere from 12 to 20 acres at each location, rather than the 10-by-20 foot plots like you might find in a typical experimental situation .”

One thing about testing biomass is that the cycle of growth in plants requires a certain amount of time. Only the time spent growing it in real world conditions can reveal crucial agronomic issues, Owens said.

“We’ve discovered that if I harvest switchgrass in August in South Dakota, I tend to hurt its chance of surviving the winter,” Owens said. “But if I wait until after the killing frost, I can almost keep that stand going, almost forever. There are going to be harvest issues like this for all of these species.”

The Terrabon Plant: A model for local ownership of commodity biomass processing?

One of the most formidable challenges for cellulose ethanol is biomass’ lack of density, according to Jim Hettenhaus a Charlotte, North Carolina based consultant. He thinks the Terrabon plant in Bryan, Texas presents the best solution to the problem yet.

To understand the Terrabon solution, think about your average silage pile, Hettenhaus said.

This technology would create a local market that would encourage a single-pass collection system. The farmer would drop the grain and the corn cobs or stover in one trip to the local grain elevator.

“To truck (all the biomass directly to the plant) is too much,” Hettenhaus said, who calculated that an 80 million gallon cellulose ethanol plant would take a million tons of biomass per year. “It will disrupt local traffic and it will tear up the roads sending that many trucks.”

He believes the answer lies at the local elevator.

“This pile at the grain elevator will become like the oil and gas wells you see when you go through Texas and Oklahoma,” Hettenhaus said. “Make it liquid right there (at the local elevator) and then pipe it to the plant for processing into fuel.”

The conversion technology would cost about million to build, and then it would cost between 0,000 to 0,000 per mile of pipeline between the elevator and the cellulose ethanol plant, he explained.

He noted that Illinois has a pilot program for this, where the biomass in the pile is treated as an asset that the farmer has just dropped off, just like the corn is treated as an asset when delivered to the elevator.

“If it’s an asset, you can arrange a loan against it, so the farmer can buy shares and finance the collection center and pipeline,” Hettenhaus said. “ This way farmers have some skin the game, and we’re not trucking huge volumes of loose biomass over great distances.”

Biomass to power corn-to-ethanol

A number of ethanol plants have begun investigating the use of clean-burning biogasifiers to replace their natural gas or coal-based power plants. Chippewa Valley Ethanol Company (CVEC) of Benson, Minnesota, working with the University of Minnesota-Morris, along with Minnesota Corn Growers Association and Minnesota’s Agricultural Utilization Research Institute, have begun running trials to research the collection of corn cobs for use in the ethanol plant’s gasifier.

“ It’s a resource in our own back yard ,” said Gene Fynboh, a farmer in western Minnesota and the leader of the research project. “We don’t have to send our money to Canada or Mexico to get the energy to run our plant. We (farmers) have been harvesting the cobs and throwing them out behind the combine. We feel it’s a very valuable resource we haven’t been using.”

The research has selected two different collection systems which offer a single-pass solution to collect both grain and biomass, but one system attaches right to the combine, while the other is an attachment that follows the machine. According to Fynboh, the project is looking not only at the most efficient way to collect the corn cobs, but also what the removal of that material does to soil chemistry and soil fertility. They are running the two systems over 5,000 acres of local corn fields this fall.

Though initially CVEC will use the biomass strictly to fire up its power plant, Fynboh believes getting the collection and transportation infrastructure in place may lead them naturally to co-locate a biomass-to-ethanol system at its facility, once the technology has been adequately developed.

Whether the biomass is collected to power ethanol plants or to produce the fuel itself, experts caution that ag-based biomass collection must be limited.

According to University of Minnesota agronomist Jeff Coulter, the removal of corn stover is best suited to highly productive fields where corn is grown continuously and reduced-tillage systems are used. In these fields, up to 45 percent of the stover can be harvested sustainably. In fields where corn is rotated with soybeans, less than 20 percent of the corn stover should be harvested on reduced-till and no stover should be harvested is aggressive tillage systems are used. However, if producers are able to apply manure or industrial by-products, such as ash, to the soil, the amount of corn stover that could be sustainably harvested increases considerably.

Tagore’s calculations assume collection of only a third of corn-generated biomass. Currently, corn production creates a total of 300 million tons of biomass a year. If the ethanol industry can eventually collect a third of that, 100 million tons, it would yield approximately 8 billion gallons of ethanol per year – almost as much ethanol as the nation produces with grain-based fermentation currently.

It could be a pretty good economic boost for the area.

 
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The American Coalition for Ethanol publishes Ethanol Today magazine each month to cover the biofuels industryís hot topics, including cellulosic ethanol, E85, corn ethanol, food versus fuel, ethanolís carbon footprint, E10, E15, and mid-range ethanol blends.
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