By Bryan Thompson
Despite all the fanfare, getting production up to speed has taken a lot longer than many people expected. Abengoa Executive Vice President Christopher Standlee said it will still be a few more weeks before the plant is producing ethanol on a commercial scale.
With the boiler up and running, the plant has produced electricity, yeast and sugar from cellulose — the material that forms the cell wall in green plants. But the company keeps starting and stopping the process to make adjustments so Abengoa can be sure it’s at maximum efficiency when it goes into full-scale production.
During a tour of the facility, chemical engineer Kevin Gross explained that the ethanol produced here essentially will be the same as that produced using corn.
“But what makes it different than any other ethanol facility is that we’re not using corn as the feedstock,” he said. “We’re using waste material, or byproducts of corn. We’re using corn stover, wheat straw, switchgrass. Any herbaceous material, we can process and we can turn it into ethanol.”
And Moniz said there’s an abundance of biomass available in the United States for ethanol production.
“The Oak Ridge National Laboratory, one of the DOE laboratories, has estimated that, nationally, we will probably have on the order of a billion tons of biomass usable for conversion,” he said.
Most of the crop residue available for use in the Hugoton facility comes from corn grown nearby to feed livestock. And growing corn requires lots of water — water that comes from the dwindling Ogallala aquifer that underlies much of western Kansas.
But that’s not the only sustainability issue. Another that’s often overlooked is the importance of crop residue to the land itself.
DeAnn Presley, an environmental soil scientist at Kansas State University, said crop residue helps prevent soil erosion and minimizes water loss.
“Anytime we have less than 80 percent of the soil surface covered, we lose water from the sun and wind, working to evaporate water,” Presley said.
So how much residue is too much to take from the soil? According to a leading expert, Ohio State University professor Rattan Lal, 70 to 80 percent of crop residue needs to be retained as a general rule.
“I did an experiment taking away the crop residue in Africa,” Lal said. “Over a 17-year period, the soil from which I was taking away all of the crop residue – it had become very hard, very cemented, very compacted. The roots could not grow through it.”
Lal said crop residue feeds the earthworms and microbes that the soil needs to grow healthy plants.
Farmers like Steve Rome understand that. He farms about 12,000 acres — mostly irrigated — around Hugoton. While Abengoa was celebrating the plant’s grand opening, Rome was on his tractor, tilling the remains of last fall’s corn crop back into a field to prepare it for planting wheat.
Rome sells some of his crop residue to Abengoa. But not from this field, where the soil is too sandy and prone to erosion. Rome considers proper land management to be more important than the money he could get by selling the corn stubble from this field.
“We look at this as a factory, and if it’s going to decrease our production levels, we won’t do it long-term,” he said. “That was an understanding when we talked to Abengoa from the very beginning. And there’s plenty of flexibility within the contract that allows us to change fields — which ones we take residue off of, and how much we need.”
Abengoa’s Christopher Standlee doesn’t think excessive removal of crop residue will become an issue. More than 15 million tons of the stuff is available within 50 miles of the plant every year.
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