Panel features southern energy crops for biorefining

By | November 03, 2010

The biorefining track at BBI International’s Southeast Biomass Conference & Trade Show got off to a strong start with a panel titled, Southern Energy Crops: Optimizing Regional Crops to Feed the Growing Biomass-Derived Energy Industry. Ross Harding with Energy Launch Partners moderated the panel of speakers. "If you can’t understand the fuel, you’ll never be able to create a commercial business," he said. "People are enamored by conversion approaches, but the question should be, ‘What fuel are we going to use?’" He said woody biomass has historically been perfected for the development of fiber, but "the right source for fiber is not necessarily the right source for fuel."

The Freedom variety of Giant Miscanthus was the focus of a presentation given by Phillip Jennings, the CEO Repreve Renewables. His company has developed a salt-tolerant variety that grows wonderfully on marginal soils. With operations in Soperton, Ga., Repreve Renewables has 400 acres of the C4 tall grass planted. "We are commercial," he told the audience. Giant Miscanthus is friendly to bird and animal populations, too, he said. Repreve planted a 10-foot buffer along a stretch of Georgia’s Red River to trap nitrates, which it did very well, he added.

Some of the benefits of the Freedom variety of Giant Miscanthus are low input costs and the relatively care-free growth after the first two years. "It’s a carbon sponge," he said, noting that Giant Miscanthus’ carbon sequestration ability is very good.

"If you plant it and forget it, it’s awful," Jennings said. "But if you do what we recommend, you’ll see high productivity." To avoid any food versus fuel debates, the energy crop has got to be grown on marginal soils, nonfood land. He said he’s often asked how far south people can plant Giant Miscanthus. "If there’s not enough frost to go dormant, don’t plant it," Jennings said, adding that it needs that punch-power the following spring. "Our stem density is higher than other varieties," he noted. The stems are smaller than other types, which gives higher yields at harvest time.

"We began with 5 rhizomes," he said. Keeping the variety true to class and pure is important to Repreve Renewables. Part of that effort involves "walking every row of the field looking for abnormalities." The flowers that produce seeds are sterile. The company employed a three-foot by three-foot spacing of the rhizomes. "You have to get it planted on time though-there’s a window of opportunity," he said.

As far as yields go, he said they achieved a modest two to three tons the first year; eight to 10 tons the second year; and 14 to 15 tons the third year of growth. "Some don’t harvest first year, I don’t know why," he said. "We do use some fertilizer, but not anything like what’s used for corn." He also said that the dense growth-5,000 rhizomes per acre-crowds out weeds. "You do need to do weed control across the top, pre-emergence. That first year it’s critical for expanded crown growth, but then the second year it is worry-free. Whether it’s done with sprayers or backpacks, weed control that first year has got to be done," he said. Freedom Giant Miscanthus also has really tight root balls. At harvest time the plant has about 12 percent moisture. Over the first three years, he said one acre of Freedom will produce 28 tons cumulatively.

Repreve Renewables has demo plots in 10 states, and in 2011 the company plans to plant 15,000 acres. He said the planting technique may seem primitive, he said the company uses old tobacco planters for dropping the rhizomes, but it works for them. Also in order to transport the finished crop economically, they need to get between 26 and 28 tons on a truck.

David Nothmann, vice president of business and product development with ArborGen LLC, presented on purpose-grown trees. ArborGen is a fully integrated company and the world’s largest producer of tree seedlings for planting. The company and has more than 100 years of tree improvement experience. They select the best of the best and asexually reproduce those varieties. "We’ve been developing a ‘growth’ gene," he said.

Benefits of purpose-grown trees for biomass utilization include low inputs and an existing, efficient harvest system. "People already know how to cut and transport trees," Nothmann said. Growers should also plant close to a facility where the product will be refined, in order to maximize those efficiencies. He said the biggest productivity gains come from improving germplasm and use of biotechnology.

"The biggest opportunity is in hardwood and Eucalyptus trees," he told the crowd.

Natural growth pine trees can achieve between four and six green tons per acre a year. With improved germplasm that number is much greater. But with utilization of improved germplasm and biotechnology, yields can jump to between14 and 22 green tons an acre.

Hardwood natural regeneration can hit modest yields of one to two green tons an acre, but with improved germplasm and biotechnology, yields spike to between 27 and 40 green tons an acre a year.

ArborGen is also working on having trees grow again after being cut, rather than having to replant. Also, planting biomass tree rows between saw timber rows is also another way to maximize land and efficiency.

"There’s growing competition for residual woods," Nothmann said, which makes purpose-grown trees, or the idea of it, that much more important. ArborGen has demo plots all around the southeastern U.S. He also referenced the Energy Information Administration’s forecast that the U.S. will require 712 billion renewable kilowatt hours by 2020. The biomass share of that will be 20 percent, he said. Of that 20 percent, 65 percent will be derived from purpose-grown trees, or 94 billion kilowatt hours. That equates to 1.2 billion seedlings planted by 2015. "So plant now," he said.

Moderator Ross Harding noted that it’s not whether scientists understand the science of these kinds of biomass projects--it’s whether the bankers understand them. "It’s about making money from making energy," he said.

The chief technology officer for Chromatin, Dave Jessen, gave a talk on his company’s developments in biomass sorghum. The technology is based on mini chromosomes, he said.

Chromatin has already licensed some of its technologies to the likes of big agriculture companies such as Monsanto, Dow Agrosciences, Syngenta and Bayer CropScience. Sorghum is a great crop he said because it’s so versatile. There are grain, sweet and biomass varieties. There are low barriers to adoption because it fits in with existing production systems, he noted.

The company’s goals are, in the short term, complete compositional analyses on what is available today; and long-term goals include biotechnology trait enhancement and "gene stacking." "We also purchased Sorghum Partners LLC, which has 40-plus years experience," Jessen said. "Today you can get a plant genotype with 20,000 snips for $20."

Rounding out the panel was Don Llewellyn, assistant professor in the department of agriculture for Eastern Kentucky University. His project is an interesting one, and involves investigating the availability of enough biomass in an 80-mile radius to feed the sugars from that biomass to enough algae to extract enough oil for a 50 MMgy facility in Clark County, Ky.

These, of course, are sugar-consuming algae, heterotrophic types grown in bioreactors. One audience member noted that radii are not good indicators of distance that must be traveled to and from a plant, which Llewellyn acknowledged.

"To get enough biomass to support 50 gallons per ton requires one million tons of dry biomass," Llewellyn said. He is looking at nonfood biomass, or biomass grown on nonfood lands, so there’s no competition with food and feed growing. Also, the biochemical characteristics need to be favorable for saccharification to feed the algae. Crop candidates include switchgrass, Miscanthus, agriculture residues, bluestems and fescues.

He said there are 14 million-plus acres in Kentucky in farms, around 52 percent of which is cropland. The remaining land is pastureland and woodland. Llewellyn said tobacco land reduction in Kentucky alone, from the tobacco buyouts, is about 22,980 acres. If that’s put into switchgrass, it would bring another 66,000 tons in the 80-mile radius from the proposed plant in Clark County. The state’s right-of-ways includes 21,500 acres, so if those were able to be planted with switchgrass, it could yield 108 million tons--but due to safety concerns, getting the state to sign on to growing tall grasses in those right-of-ways is not likely.

He concluded by saying there is indeed sufficient biomass to fuel a 50 MMgy algae facility within an 80 mile radius of the Clark County proposed plant. "There are actually eight different potential zones like this in the state," Llewellyn said. "We’re focused on getting the sugars out of the biomass for the algae, and then the algae people will do their magic from there on."