Tennessee’s Biomass Innovation

Genera Energy is applying a systems approach to developing customized energy crop supply chains.
By Sue Retka Schill | January 30, 2014

It is often said finding the right answer is predicated on asking the right question. The tongue-in-cheek answers to key questions on Genera Energy’s website summarize well the challenge of building the new biomass energy economy: Which feedstock is best? Well, it depends. Where is the optimal location for a biorefinery? Well, it depends.

What’s the best method for collecting, harvesting, storing, transporting biomass? Well, it depends. How much does a ton of feedstock cost at the farm gate? At the biorefinery gate? Well, it depends.

Genera Energy aims to help clients answer those questions using a systems approach to developing customized supply chain solutions. As it wrapped up a five-year biomass supply chain research grant for the U.S. DOE this fall, the Tennessee-based company has begun working on projects large and small across the country. Sam Jackson, vice president of business development, declined specifics, but says it is more than three projects, more than one feedstock, and includes projects focused on cellulosic ethanol, biopower and biobased products. 

There have been a number of twists in Genera Energy’s development path. There had been ongoing research for several years on switchgrass as an alternative crop, when, in 2007, the state committed $70.5 million to demonstrate an integrated bioeconomy. A switchgrass demonstration program offered incentives to farmers to grow the new crop, ultimately recruiting more than 60 farmers within 50 miles of Vonore, Tenn. Research on best agronomic, harvest, storage and handling practices was expanded. 

Addressing the chicken-and-egg challenge of developing a feedstock and conversion technology simultaneously, the university began looking for an industry partner to build a demonstration-scale plant at Vonore to convert switchgrass to cellulosic ethanol. When initial negotiations with Mascoma Corp. stalled, the university changed course and signed a joint venture agreement with DuPont Danisco Cellulosic Ethanol, which later became DuPont Cellulolsic Ethanol LLC when DuPont acquired its joint venture partner. DuPont was willing to work with switchgrass but was also interested in using corn stover, so the Tennessee project expanded to encompass a broader range of feedstocks. Indeed, the researchers have now worked with most of the feedstocks being proposed for cellulosic conversion, including miscanthus, biomass sorghum, sorghum sudan, sweet sorghum, hybrid poplar, arundo donax and sugarcane bagasse.  

LLC to C Corp
As the programs developed early on, Jackson explains, “It became evident that the university needed a business arm to manage the initiative.” Genera Energy LLC was formed in 2008 by the university’s research foundation to take on that role. “As we moved forward with the switchgrass supply chain and other activities, it became evident that the contract and farm management skills that Genera developed over time were going to be needed in the marketplace.”  In 2012, Genera Energy Inc. was spun out as an independent C corporation, and the original business was renamed TennEra LLC. TennEra owns the 250,000-gallon-per-year demonstration plant in Vonore, operated exclusively by DuPont Cellulosic Ethanol, and has taken on Genera’s academic functions, moving promising academic research forward to the precommercial demonstration stage. 

Genera Energy continues to operate the Biomass Innovation Park on 22 acres alongside the demonstration plant, built with the help of the five-year, $5 million DOE grant. “It helped us learn a tremendous amount about bulk handling of switchgrass and other herbaceous feedstocks,” Jackson says. Using existing equipment in new, efficient ways was important to reducing costs, he says, as well as optimizing “the dance of logistics in the field with trucks and equipment.” No new equipment was developed as part of the project, he adds. “What is unique here is the way we’ve put all of that equipment together.” One example is the use of the compaction technology developed for urban trash handling to double the bulk density of field-chopped switchgrass, cutting trucking costs in half. 

On the receiving end, Genera experimented with eight to 10 different feedstocks. “We’ve learned about the handling of those feedstocks and how to adjust to prevent problems,” Jackson says. For instance, there is a big difference between a feedstock that’s been field-chopped using forage equipment with cutting knives that leave clean-cut edges versus the same feedstock that is reduced to similar particle sizes using a hammermill-type grinder with a shredding action that leaves furry edges. With proper adjustments, both flow through the system efficiently, Jackson says, adding that each feedstock has its own handling characteristics. The realization that this knowledge base is both unique and needed in the emerging marketplace is a big reason Genera Energy went commercial.      

Jackson explains Genera is now focused on working with clients to choose from all available feedstock and equipment options to customize a supply chain system, starting with land acquisition, farmer contracts, agronomic management, harvesting logistics and preprocessing. “We’ll get [the feedstock] to a spec product at a plant gate because we feel the most efficient way to manage the supply chain is to have it integrated all the way through. Multiple contractors doing multiple pieces is not necessarily the most efficient way of doing this,” he explains. Genera has developed and trademarked Supply ASSURE, software that incorporates financial accounting, labor management and data from the field through preprocessing. It also offers a proprietary and trademarked BIN-SPEC material handling and milling system. 

Switchgrass Succeeds
Switchgrass, where the Tennessee initiative began, is still likely to be the feedstock of choice in the state, Jackson adds. While energy crops like miscanthus and biomass sorghum offer impressive yields and real advantages in certain situations, switchgrass will have its place. In the Tennessee evaluations, yields in the best soils and locations have met the 8-dry-ton-per-acre target, he says. More importantly, the perennial grass has been demonstrated to do well on less productive land that typically is not in row-crop production, yielding 6- to 7-dry-tons per acre. “Then, when you couple that yield with management costs, which tend to be fairly low because it’s a seeded feedstock like sorghum but perennial, plus low fertilizer needs on an annual basis and fairly low intensity in terms of management, it comes out to be a fairly low-priced feedstock,” Jackson explains. “In this area, this region, switchgrass will be the fit.”  

Author: Susanne Retka Schill
Senior Editor, BBI International