The best logistics for harvesting energy sorghum standing taller than 10 feet are still under construction, experts say. But principles developed in the 1970s for making cotton modules are being used today for bioenergy production.
Researchers say there's potential for another breakthrough innovation for Texas AgriLife Research, the agency that in the 1970s pioneered cotton-harvesting technology used today across the Cotton Belt.
Engineers with AgriLife Research recently demonstrated sorghum modules made with a modified cotton-module builder during an international media day in College Station.
“Lambert Wilkes developed the technology with Texas AgriLife Research here a couple of decades ago and solved the problem of how to harvest cotton material and store it after transporting it from the field,” Dr. Stephen Searcy, an AgriLife Research engineer told a group of journalists. “That’s what we’re trying to do in biomass logistics. Biomass has a very low energy density and takes lots of plant material to supply a conversion plant.”
The process involves the harvester transferring the sorghum to a silage wagon. Next, the silage wagon travels to the module builder and transfers the material. The biomass is compressed into a module and encased in a protective cover that is applied before being transported to an energy facility.
There are obstacles to overcome, Searcy said. The tall energy sorghum, developed by AgriLife Research plant scientist Dr. Bill Rooney, contains lots of water, making it a challenge to compress the biomass material into a single module.
“We’ve got huge quantities that in the end we have to deliver at a feasible cost,” he said. “While we are using cotton equipment to prove the concept, new machines optimized for energy biomass will be needed.”
To be economically viable, the crop has to be harvested, moduled and trucked to an energy facility.
"The effective economic radius will be determined by the efficiency of the logistics system, and we are working to expand that travel distance," Searcy said.
“It takes lots of material, we’re talking huge quantities and the farther the travel distance, the more the costs,” he said.
Meanwhile, investigating how energy sorghum can be a sustainable crop in a farmer’s portfolio is another aspect of the work done by AgriLife Research scientists and specialists with the Texas AgriLife Extension Service.
“We really see this crop as another the farmers can have in their portfolio,” said Dr. Juerg Blumenthal, AgriLife Extension agronomist.
Rooney said he thinks farmers will want the choice for energy sorghum to be an annual crop.
“I think farmers are more reluctant to commit to perennials,” he said. “They can come into one season, then they can rotate to another crop if they want to.”
For more on the AgriLife Research bioenergy program, visit http://agbioenergy.tamu.edu.