Next Step debuts corn stover pellets

By Anna Austin
Posted December 8, 2009, at 5:00 p.m. CST

After a series of rigorous operational and burn characteristic assessments, Nebraska-based Next Step Biofuels is ready to move their corn stover pellets into marketplace, and told Biomass Magazine negotiations are underway with several Midwest power utilities for supply contracts to begin next year.

Will Gardenswartz, Next Step director of marketing, said all of the testing has been completed with satisfactory results, including the manufacture of the pellets at a commercial scale. Several months ago, Next Step worked with Loup Valley Alfalfa's pelletizing facilities in Burwell, Neb., to perform production tests, according to Gardenswartz. "We retrofitted the facility with what's needed to make our corn stover pellets-which is different-and we produced them there for a period of several weeks," he said.

Next Step also had operation tests conducted at the Energy & Environmental Research Center at the University of North Dakota.

There are two main advantages to "Power Pellets" over wood pellets, Gardenswartz said. "Processing characteristics is one. What's necessary, in order to fold this into a coal-fired plant operation, is to pulverize whatever they plan to co-burn in the same way they do coal. Wood pellets are typically very difficult to pulverize, as they are often made with binders. Binders create undesirable substances in the ash which can cause slagging problems, and you don't want to introduce impurities from the binders into the system."

The other advantage is the economics of using corn stover as a pellet feedstock, according to Gardenswartz. "Being that corn stover is the most abundant biomass source in the U.S., in theory, they will sell for less than wood pellets," he said. "One problem with the wood supply market is that although they say it's renewable, if you look at the numbers on leftover waste wood and lumber resources, you'll see a lot of pressure."

Though the company hasn't yet built its own pellet plant, Gardenswartz said major off-take agreements with utilities will influence where and when one or more will be built. "For a lot of reasons, as you can imagine, we'll put the plants really close to where the pellets will be used," he said. A typical plant will produce 175,000 tons of the pellets annually, each pound containing just less than 7,300 Btu. The Midwest will host the plants, he added, due to an abundance of corn stover throughout the region. "We're actively contracting for corn stover right now and are seeing success doing that," he said. "These are seven-year, price-stable agreements, and involve a turn-key program. We come in, harvest, bale and shred the corn stover, using our own combines and crews."

Addressing concerns surrounding the possible effects corn stover removal might have on the quality of soil, Gardenswartz said it won't be a problem. "While leaving a certain amount of corn stover in the field is important for the soil, yield increases in corn have actually created a corn stover surplus, and leaving too much is a problem."

Though admitting that while no pellet will compete with the cheap cost of coal, Gardenswartz emphasized the point of utilizing biomass pellets is beyond cost competitiveness. "Using them will be necessary to comply with state renewable portfolio standards, carbon credit gains, and will become especially important with the new U.S. EPA greenhouse gas ruling. Though the pellets could cost three to four times as much as coal, using them is all about reducing carbon dioxide emissions."

Biomass pelletizing is far from a new concept, Gardenswartz pointed out, but corn stover is a particularly stubborn substance to pelletize. "The reality is that people have been producing biomass pellets for a long time, but corn stover has been resistant for a variety of reasons-it just has bad processing characteristics. It took us a long time to figure out, but now we've solved the problem and have a novel, cost-effective process."