The Breadbasket’s Biomass Belt

The U.S. Midwest has considerable biomass energy potential, specifically in anaerobic digestion applications
By Anna Austin | February 21, 2012

Any visitor to the U.S. Midwest knows the region isn’t recognized for glorious mountains, warm weather or sunshine. It does, however, boast flat and vast plains, long stretches of grassland, and highly productive soil that allows it to produce an abundance of cereal crops.

To some, that’s an ideal scenario for growing a biomass energy industry off the back end, and numerous industry experts are busy examining its viability and potential impacts. As with any emerging industry, there are some hurdles and kinks to be worked out, but there is a resounding consensus across the scientific community that Midwestern crop residue and cattle manure will play a key role in the region’s energy future. In fact, one recently published, USDA-backed study has determined that biomass alone could be used to produce 15 percent of the Midwest’s electricity.

Assessing Availability

Authored by Chicago Council Senior Energy Fellow Steve Brick, “Harnessing the Power of Biomass Residuals: Opportunities and Challenges for Midwestern Renewable Energy,” considers the residual biomass resources of Illinois, Indiana, Michigan, Minnesota, Ohio and Wisconsin. According to Brick, the year-long project involved three main steps: preparing a regional residual biomass inventory, developing an assessment of conversion technology readiness and economics, and developing policy recommendations.

Brick’s team arrived at its 15 percent of Midwest electricity conclusion by converting all of the “ecologically available” biomass to dry tons, and assuming it would be burned in a conventional boiler.  “This was done as a way to bind the total contribution that waste biomass could make to the regional energy supply,” he says. “We made the same calculation for ethanol—assuming all the biomass could be converted—and found that 17 percent of the region’s gasoline could be supplied from biomass residuals.”

Residuals included in the report are crop residues such as corn stover, soy straw and wheat straw; manure from swine, cattle and poultry; and forestry, primary mill and urban wood residues. While corn stover leads in crop residue annual tonnage at 106 million tons, Brick points out that the logistics of harvesting, transporting and storing corn stover are uncertain. “Questions of how much stover can reasonably be harvested, who harvests it, how it is harvested, transported and stored must be addressed before a new industry can take shape,” he says. “We really need to consider biomass energy systems in the broader landscape contexts in which they occur. The land-water-air-wildlife-human interactions are critical, but easy to ignore if we just consider biomass as an energy resource. A landscape perspective is harder to develop and talk about, but it is really the key to smart protection and utilization of our natural resources.”

Unlike corn stover-to-energy, the anaerobic digestion (AD) industry isn’t new to the Midwest. It is already home to 52 of the nation’s 169 anaerobic digestion projects. Most of the digesters are concentrated in the Great Lakes region, but the 33 MW contribution to the regional energy supply represents only 2 percent of installed capacity, according to Brick. He believes AD energy potential in the region is huge, even though it is challenging financially. “AD is a great technology for producing biogas for use in a turbine, as a boiler fuel or a transport fuel, and a great way to reduce water quality issues associated with manure and reduce greenhouse gases,” he says.

Digest This

Currently, only about 1 percent of the Midwest’s cattle manure is managed through AD, and digesters are found on only about 10 percent of the region’s largest dairy farms. With the amount of manure available—14 million tons annually from cattle alone—why aren’t more farms taking advantage of the technology?

“I think there are several reasons why,” says Amanda Bilek, energy policy specialist for the Great Plains Institute. “Part has to do with public policy, and a lack of support in individual Midwestern states with the exception of Wisconsin, which is a shining example for the other states. They’ve done better than any other Midwestern state by collaborating with state agencies, producer associations, and leveraging some federal resources.” 

Wisconsin has the most AD installations of any state in the country, according to Bilek.
Outside of the policy realm, another factor influencing the lack of AD projects is the low price of electricity in the Midwest. “A lot of AD project models have been focused on producing renewable electricity, but we have very low prices in the Midwest overall,” Bilek says. And because digesters require a large capital investment, selling the resulting electricity in the Midwest often means a really slow return on investment. “That deters some producers from installing them, because they can be viewed as risky.”

Biogas doesn’t have to be converted into electricity, though. “It can also be a source of renewable natural gas, cleaned and compressed even further into vehicle fuel, or a source of heat in certain applications,” Bilek says. “If we only look at one specific type of utilization of the gas—electricity—we’ve really missed the potential opportunities there.”

The low price of natural gas is another AD hindrance, according to Brett Hulsey, president of Better Environmental Solutions, a Wisconsin-based clean energy consulting, managing and development firm. “Actually the biggest challenge in the biomass industry as a whole is cheap natural gas—at $2.50 per 1,000 cubic feet, energy efficiency barely pays,” he says. “I’ve been at this 30 years, and I’ve seen natural gas take a wild swing.”

Hulsey, also a Wisconsin state legislator and a Dane County board supervisor, served as an environmental policy advisor to President Bill Clinton and worked as an environmental educator and advocate for the Sierra Club for 17 years. He says another hurdle to widespread AD implementation and bioenergy in the Midwest is getting farmers to understand the right amount of manure and corn stover to put back on the soil. “Any more than [the right amount] results in more phosphorus and nitrogen pollution,” he explains. “This industry is also part of a water quality improvement solution, because when you have too much manure or corn stover on the soil it creates water pollution.”

 For corn stover, the adequate amount is about two to three tons per acre, but manure varies greatly. “A lot of soil in Wisconsin doesn’t need more phosphorous,” he says. “So if we can separate the biomass out of the manure—we’re actually doing that at a pilot project in Dane County, separating liquids from solids after the digester—the phosphorus stays with the solids.”

Despite the aforementioned challenges, AD development has continued in the Midwest over the past decade. “It’s been slowly increasing, and there are some real pockets of significant development, especially in Wisconsin,” Bilek says, adding that since the state is home to a manufacturer of an AD technology, producers likely feel more secure having someone in their backyard to help with trouble shooting.

In Minnesota, the number of digesters has tripled from two to six in the past 10 years, and other states in the region have had similar increases. “That’s not a huge amount of growth, but its growth,” Bilek says. “We just have to get the technology over the first hump. Creating more incentives would help, at least to get over the initial economic barrier until more systems are installed and the costs come down.”

And once the AD and biomass energy industry in general gets rolling in the Midwest, so will new employment.

Jobs and More

A 2007 analysis performed by Hulsey found that the industry could create 100,000 jobs in Wisconsin alone. “We import $12.5 billion worth of energy per year for coal, oil, and natural gas, and conservatively that’s a 100,000 job loss,” he explains. That’s following a rule of thumb for one job created for every $50,000 kept in state. “Iowa generates about 39 million tons of corn stover per year, and they are already generating more fuel than they use,” Hulsey says. “They import about 20 million tons of coal a year, but they could be almost energy self-sufficient. That’s one of the next studies I may do, an energy import study, to really hone in on the jobs question.”

Speaking of replacing coal, in another of Hulsey’s 20 studies, “Cellulose Prairie: Biomass Fuel Potential in Wisconsin and the Midwest,” he found 12 Midwestern states generate up to 231 million tons of potential excess biomass each year that could replace 37 percent of the coal used in those states, 50 percent in Wisconsin alone. Hulsey says coal replacement conversions were a key concept in the study, as previous data hadn’t put information in such real terms.

Moving on to other Midwestern benefits, one environmental advantage not often associated with biomass energy is reduced flooding. “Many studies have shown that planting cropland to grasslands, combined with other conservation practices, can reduce 100-year floods by 15 to 39 percent,” Hulsey says. “Basically we’re restoring nature’s sponges—especially with grassy biomass—that store flood waters. I worked on a project two years ago where we restored a wetland area to both willow and switchgrass, and the idea there was to build more of nature’s sponges to reduce water on the land and in people’s living rooms.”

While biomass is usually snubbed in the energy portions of typical presidential speeches touting home-grown fossil fuels and other sources of renewable energy, it plays a significant role in the country’s current energy portfolio. “Biomass is the Rodney Dangerfield of energy—‘we don’t get no respect,’” Hulsey jokes. “But really if you look at (U.S.) DOE numbers, it equals about half of renewable energy in the U.S., especially here in the Midwest and in Wisconsin.”

Overall, the important thing to remember about biomass fuel is that it’s all local.  “You have to set your fuel systems up according to what you have,” Hulsey adds. “For example, Iowa has corn stover. The Saudi Arabia of America is right here in the Midwest, and while we aren’t a Silicon Valley, we can be the ‘cellulose prairie,’ making our own energy and jobs.”

Author: Anna Austin
Associate Editor, Biomass Power & Thermal
(701) 751-2756