Montevideo, Minn. — David Eid, a former corn farmer who grew up in sugar-beet country, is championing sweet sorghum for fuel. Why advocate growing the nontraditional sugar crop in corn territory? Because sweet sorghum produces more sugar with less inputs than beets per acre, and it doesn’t have to be converted from starch to sugar before fermenting to ethanol, as corn does.
Eid’s start-up company, Encore Bioenergy LLC, has constructed a small demonstration plant that will eventually make ethanol from sorghum and other high-biomass crops — after trial runs with corn. Though his original vision was to build a full-scale sorghum-ethanol plant, Eid downsized to a portable facility on a semi-truck trailer bed. In the process, he discovered his small plant’s greatest value may be in applied research and training, rather than making small batches for personal or commercial use.
Encore Bioenergy’s plant will produce 200,000 gallons of fuel per year. The system uses a simple conversion, with basic enzymes, to convert sorghum juice to ethanol. “The juice doesn’t require the long fermentation process and cooking time needed for corn-based ethanol,” Eid says.
Eid briefly considered using the plant as a model for replicating nationwide for smallscale ethanol use. “Farmers were interested in, ‘Could I buy one and make fuel for myself?’ But you realize that having a thousand of these floating around the countryside could be a big challenge. We need to monitor these facilities. It’s probably a training vehicle.
“I’m cautious about promoting small-scale ethanol production to be perfectly honest.”
“I’ve gone down the road of, ‘let’s build a plant so we can process a few thousand acres of sorghum’ to a small scale. But we always ended up with the same types of problems — storage and start-up. How do you scale up to a size that makes sense from 0 to 60? So that’s what led to building a 10-million gallon plant on a 1/50 scale and once we were building that, there was interest.”
This year, an investment group expressed interest in using Encore’s sorghum-ethanol system to build a 10-million gallon system “because they don’t want to build a cornethanol plant in the current environment and they know cellulosic isn’t ready.”
He convinced them “to start with a 200,000-gallon facility so they can work on developing test plots, growing 200 acres the first year and putting on a complete demonstration while they are educating farmers, generating enthusiasm and raising money.”
For decades, sorghum has been tested for Minnesota ethanol production as it yields up to twice the fuel of corn per acre, and fermenting sugars into ethanol is a one-step process. But sorghum will rot in piles and can’t be dried and stored in bins like corn, so most groups interested in using Encore’s sorghum-ethanol system are in “southern states where they can raise and harvest sorghum nine months out of the year,” which solves the storage problem, Eid says. “Transporting sorghum any distance is not feasible — 20 miles is the maximum.”
Eid has been working with chemists in Maryland on converting biomass to liquid sugars in the field, and the syrup could be stored and transported. But that technology “won’t be available for a couple years,” he says.
“It’s been a challenge because I started this whole project with an enthusiastic attitude. Within the first year, I went to Watertown, S.D. and gave a presentation in front a whole bunch of people — from the governor’s office to growers. There was a warm reception to the concept, but I didn’t have answers to all their questions like: ‘If we invest in growing a plant like sweet sorghum, are the fuel-processing systems sufficient? What do processors use the other eight months of the year when sorghum isn’t available?’ ”
That’s why Eid says he deployed the portable demonstration unit. “We have worked toward answering those questions.”
From corn to sorghum
A North Dakota State University graduate, Eid farmed in the Montevideo area for 25 years, then spent five years brokering commercial real estate, primarily farmland. “Partway through that I became interested in advanced biofuels, because obviously I raised a lot of corn and spent a fair amount of time promoting corn ethanol. So I’m certainly not anti-corn ethanol.”
“Then I just basically got interested in sweet sorghum,” and building an ethanol facility that used the sugar crop. “Even though I was on the Internet, looking all over the world, there was almost nobody doing it yet — just a little in China and India.”
Sweet sorghum, native to Africa, was introduced to the United States in the 1600s but not grown extensively as a forage crop until the 1850s. Eid says the United States funded considerable research into growing sorghum for ethanol during the 1970s oils crisis, and high-yield, high-sugar varieties were developed.
The annual crop can be planted with a grain drill or corn planter in late spring or early summer. Warm soil is needed for germination, but cold-climate varieties are being developed that can be planted in early April to allow for two cuttings over the growing season. Eid says sorghum tolerates drought and some flooding better than corn, grows well on marginal lands and produces high yields in a short growing cycle with minimal fertilizer, pesticide and irrigation.
Most U.S. sweet sorghum is grown in the Great Plains where rainfall is too low and temperatures too high for profitable corn production, such as Texas, Kansas and Nebraska, although some sweet sorghum has been grown in Minnesota and Wisconsin for silage and syrup, which is extracted by crushing the plant stalk. The syrup is used primarily as a food-sugar substitute and a livestock-feed ingredient.
Eid’s business plan states that University of Nebraska-Lincoln research finds “there’s enough juice in an acre of sweet sorghum to make 400 to 800 gallons of ethanol,” and with intensive plant breeding and cultivation research, could reach 1,000 gallons — or even more with cellulosic technologies. In comparison, Eid says an average corn crop yields 420 gallons of ethanol per acre.
Between corn and cellulose
For now, Eid says sweet sorghum may be an acceptable intermediary as the ethanol industry moves from corn to non-food cellulose.
He recently spoke on processing sugar crops into ethanol at a national biofuels conference in Washington D.C. that focused on such developments as thermochemical conversion, algae biodiesel and cellulosic ethanol.
Eid was surprised by negative attitudes toward corn ethanol when it “built the industry. There are some really good attributes to corn – it’s readily available, stores easily and there really are no waste products … we can use the distiller’s grains.
“The cellulosic-ethanol panel was asked when we’d see cellulosic on the market and the answers ranged from 2011 to 2014. When asked, ‘what have you done for collection and delivery?’ there wasn’t an answer.”
“I hope somebody makes progress on cellulosic — and we can triple our gallons per acre. But we have to start somewhere.”
Conference participants interested in building cellulosic plants “assume that farmers will just show up at their door with trucks of biomass. From my 25 years of farming experience, I know it’s not that way and if you’re going to introduce a new crop — sorghum, switch grass — there’s a lot of issues involved. You need the farmer to have a comfort level with the new crop and their lender also has to be convinced. Who is going to withstand the production risks? And can it compete with traditional crops?” Eid says.
“Sitting in the audience, listening, it became really clear that there wasn’t enough sympathy for corn ethanol and there was too long of a time delay before cellulosic is going to have an impact.” With sorghum ethanol, “we can fill the niche in between – and help build the infrastructure.”
With the help of Doug Root, AURI biofuels scientist in Marshall, Encore’s ethanol plant recently completed its first test run using corn feedstock “to benchmark where we fall in the industry” before converting to sweet sorghum, sugar beet pulp or other biomass, Eid says.
“It provides a platform for things we hope to demonstrate,” such as non-distilled, continuous ethanol production that is less expensive than the current batch process, Root says. “We might be able to demonstrate the process on a small scale and come up with an estimate of the energy required to produce pure ethanol without distillation on a large scale.”
AURI is also employing the plant to investigate butanol — a biofuel that has 95 percent of gasoline’s Btu’s versus 73 percent for ethanol. Butanol can be used in existing internal combustion engines and can be blended at any rate with gasoline.
The Encore Bioenergy company is “right now just me and some private investors,” Eid says. “But I have a team of people helping push things along — from a legal team to engineering to a capital-raising firm to community development to research. … They believe in it.”