Energy sorghum demonstrates potential during dry summer

By Dan Conable, Cato Analytics LLC | September 18, 2012

Despite weather challenges and the learning curve for farmers unfamiliar with this energy sorghum, one of the first commercial-scale plantings of the crop in the northeastern U.S. has been a success.

More than 400 acres of ES 5200, a high-biomass sorghum developed by Ceres Inc., were planted in June and early July under contract with Sweetwater Energy Inc., a bioproducts company focused on extracting sugars from a wide range of biomass feedstocks.  In addition to the commercial acreage, strip trials of other sorghum varieties supplied by Ceres were planted on three farms to provide Sweetwater with more material for testing in its pilot research facility in Rochester, N.Y.  A study of the economics of energy sorghum production from the farmer’s perspective is ongoing, with sponsorship by the New York Farm Viability Institute, a state-funded applied research organization.

At a field day for Western New York farmers, Jack Baron, Sweetwater’s president and CEO, explained the Sweetwater business model.  “Rather than battling the logistic challenges of bringing hundreds of thousands of tons of feedstock in to a single processing facility, we’re working with a ‘hub and spoke’ model,” he said. “We will put up modular plants to extract sugars from about 40,000 tons of feedstock in locations where that material can be easily assembled, and then deliver sugar—a much higher-value product—to end users in the biofuel and chemical industries.”  Sweetwater’s first commercial plant, to be announced within the next few weeks, will be located in the Midwest and utilize milling byproducts.

“Sorghum has a number of advantages over many of the energy crops currently under development,” observed Chuck Kyle of Cato Analytics LLC, who has headed up recruitment of growers and technical support through the growing season. “It’s an annual crop, which means that farmers can gain experience as growers without making a long-term commitment.  Sorghum can be planted and harvested with conventional equipment, and it doesn’t have to be planted early to produce a good crop.” 

On the farm in Albion, N.Y., where the field day was held, the energy sorghum was standing higher than the corn crop next to it, even though it had been planted almost a month later.  Kyle explained that the option of planting as late as early July opens a window for double cropping with winter wheat, as well as early vegetables in a region where producing canning vegetables is an important part of the local farm economy.

Although a few of the fields planted this year did show the effects of a very dry July, the fact that the crop keeps growing until the first frost has given it an excellent chance to catch up to its expected yield, which can exceed 10 dry tons per acre by the end of the growing season.  Bud Wylie of Ceres, who spoke at the field day on behalf of the company, observed that while New York may have a somewhat shorter growing season than the South, long day lengths go a long way to compensate.

One challenge of harvesting the thicker-stemmed hybrids in this part of the country is that moisture levels can remain about 60 percent, even after a frost. High moisture doesn’t affect the sugar extraction process, but it can be an issue for feedstock storage. To avoid the cost of drying a crop that will be processed wet, Sweetwater has explored ensiling the sorghum in the same manner as corn silage in covered bunkers, with material removed for sugar extraction as it is required.  The company’s research program is currently focused on management of this type of wet storage to optimize sugar extraction from the ensiled feedstock.

Despite the dry weather, Sweetwater’s contracts with growers have resulted in output that exceeds the requirements of Sweetwater’s current pilot-scale research program at its Rochester, N.Y. facility.  This situation has illustrated another advantage of this versatile crop: it can be readily incorporated into cattle feed. Faced with a critical forage deficit as a result of the dry summer, farmers in the area have been happy to purchase the surplus energy sorghum for incorporation into dairy rations.