The world of cellulosic ethanol, which has taken a long time to come to fruition, is now a reality. Last month we reported on two plants in Iowa that are on line, or will be soon. This month we look at a diversified operation in Kansas and how it’s shaping biofuels’ future.
Abengoa Bioenergy celebrated the grand opening of its cellulosic ethanol biorefinery in Hugoton, Kan., last month. With a nameplate capacity of up to 25 million gallons per year, the Hugoton plant is beginning to produce cellulosic ethanol from corn stover and wheat stubble. It also will produce up to 22 megawatts of electric power. The plant will gradually produce fuel from various agricultural residues, such as milo stubble, switchgrass and other energy grasses.
Between 150 and 200 growers from within a 100-mile radius of Hugoton are supplying feedstocks to the facility. “Once we are at full capacity, we will use up to 340,000 dry tons of biomass per year,” says Tom Robb, manager of institutional relations, Abengoa Bioenergy.
Abengoa is no stranger to the energy business. With U.S. operations in Chesterfield, Mo., the company generates electricity from renewable sources (solar, cogeneration and wind) and produces biofuels. It operates in more than 70 countries through five business units: solar, bioenergy, environmental services, information technology, and industrial engineering and construction.
Before beginning construction on the Hugoton plant, Abengoa Bioenergy produced cellulosic ethanol from corn stover at a pilot plant in York, Neb., and cellulosic ethanol from wheat and barley straw at a demonstration plant in Salamanca, Spain.
About seven years ago, Abengoa held the first focus group meetings with growers from the Hugoton area on how ag residues could be removed from fields on a long-term, sustainable basis. Erosion was a concern because of strong winds in the area.
Custom harvesting model
The company evaluated studies conducted by USDA’s Natural Resources Conservation Service on partial residue removal and recommended its models based on crop, yield, soil type and row spacing, Robb says. Abengoa also entered into an agreement with Pacific Ag LLC, Hermiston, Ore., for comprehensive supply chain development and operation, including crop residue harvesting services. Pacific Ag also delivers the feedstock to the Hugoton facility.
Pacific Ag provides custom harvesting services to Poet and DuPont Industrial Biosciences, too, says Bill Levy, founder and CEO, Pacific Ag. As the largest custom harvester in the U.S., Pacific Ag has been operating commercial-scale crop residue supply chains for 16 years. It operates in eight states: Kansas, Iowa, Nebraska, Oklahoma, Texas, Washington, Oregon and North Carolina. It started out harvesting residue for domestic and export forage markets. “We saw a natural progression of our services for the biofuels industry,” Levy says.
“We like working with Pacific Ag because it’s a one-stop shop,” Robb says. Abengoa stores about a one-month supply (27,000 to 30,000 tons) of biomass at Hugoton, while Pacific Ag stores the remainder of harvested residue at various locations. This is done to spread the risk of fire, especially during a windstorm.
“Eighty percent of what we harvest for Abengoa is corn stover, and the rest is wheat straw,” Levy says. The harvest crews remove between 1.5 tons and 2 tons of residue per acre, depending on the grower’s soils, yields and management practices. “We leave enough residue to prevent erosion. There also is enough residue left for nutrient replacement,” Levy says, noting growers in Kansas, who have had nearly a decade of drought, are rightfully apprehensive of losing soil to wind erosion. Due to the prolonged drought, residue also has increasingly been used for animal feed.
Area growers are seeing benefits to partial residue removal. Tab Beck farms 3,200 acres of corn, wheat and milo on sandy loam clay in the Texas and Oklahoma Panhandle. Removing about 2 tons per acre of residue saves him a tillage trip.
“At $14 to $15 per acre in fuel savings, that’s a benefit,” he says. Partial removal improves seed-to-soil contact in spring, which means better emergence, he says. No-till farmers in his area must reduce residue because they have not had rains to help break it down, he adds. Beck acknowledges wind erosion as a concern. But he adds that it has not been a problem on his farm, even last year, which was one of the area’s windiest seasons in some time.
Steve Rome and his brothers, Keith and Dave, grow about 12,000 acres of corn and wheat on silt loam soil with some clay near Hugoton. About 75% of their crops are irrigated with water from the Ogallala Aquifer. “This is a finite resource, and we are constantly looking for ways to be more efficient,” Rome says.
The area receives about 17 inches of rain a year, but considerably less during the recent drought. “Our grain and stover yields are dependent on rainfall or irrigation. With the drought, we must decide how to manage water to be profitable.”
The Romes’ average corn yield is 215 to 220 bushels per acre. They have some sandier soils on hilltops, where they plant wheat to stabilize the soil. Residue is not taken from these hilltops. On their land with heavier soil, Pacific Ag removes about 50% of the residue.
The Romes farm in a wide-open area, where strong winds can blow from March through May. The residue, shifted by wind, can accumulate in areas to as deep as a foot or more, despite farmers’ efforts to spread residue. When residue piles up, emergence is delayed and can result in uneven or spindly stands, which can affect yields in both corn on corn and double cropping (wheat following corn). To keep the material from mounding up and to provide a better planting environment, more area growers have adopted strip till, Rome says.
“We haven’t seen a yield advantage from removing residue, and we know that we’re going to give up some nutrients,” Rome says. “But removing residue through partial harvest does help establish a better seedbed.”
Both growers see benefits of using custom harvesting services. “Pacific Ag was in and out in two days. That allowed me to begin planting wheat right away,” Beck says.
The Romes considered investing in their own biomass harvesting equipment. But because the equipment would only be used for biomass, they opted to use the Pacific Ag crew. “The learning curve for our crew also would have been very high for running this type of equipment,” Rome says. “This has been good for us. We need to consider our window of fall operations.”
Right after harvest, the Romes begin preparing for the next year’s crops and maintenance work on the farm’s irrigation equipment and other machinery.
To make custom harvesting and transportation operations as cost-efficient as possible, Pacific Ag uses high-density large square balers. Over the last few years, the company has found that AGCO Massey Ferguson balers have run reliably, requiring the least amount of downtime, Levy says.
The Pacific Ag crews use ProAg Stackers. One model can stack 12 bales at a time, while another stacks six at a time. Bales are stacked at the edge of fields, where they can then be loaded onto flatbed trucks and transported to the storage site. Up to 42 bales at a time can be loaded on the trucks.
Harvesting biomass for cellulosic ethanol and other biobased products is in its infancy. “But I think it is here to stay,” Levy says.
For certain growers, the agronomic value of residue removal may be even more important than what they get paid per ton of biomass. Other growers will appreciate the extra income, plus the benefits of residue removal.
Chris Standlee, executive vice president of Abengoa Bioenergy, told an ethanol workshop this summer that the amount of biomass expected to be purchased for Abengoa’s Hugoton plant could help inject $17 million into the local economy.
“We’re happy to provide farmers another source of income. This is a good opportunity for all involved,” Robb says. “Abengoa has a world view on energy. Over the long term, energy consumption is only going to increase. We think cellulosic ethanol will play a big role.”
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