This summer's drought has "stirred the pot" in the fuel vs. food debate, but researchers at the University of Missouri Center for Agroforestry are collaborating with the U.S. Dept. of Energy to study how second generation biofuels—those from non-fuel crops grown on marginal land—could become profitable and sustainable.
Despite finite supplies of fossil fuels, Shibu Jose, director of the Center for Agroforestry at the University of Missouri and H.E. Garrett Endowed Professor at the MU College of Agriculture, Food and Natural Resources says creating a vibrant biofuel industry is a "chicken-or-the-egg" problem.
Farmers don't want to invest in these biofuel crops until they know there will be buyers willing to pay a good price for them, he says. "And industrial players like refineries and producers of advanced liquid fuels would like to see sustainable production of biomass crops before they set up shop, which would take millions of dollars of investment."
To find solutions to both cropping and processing issues, MU researchers are testing four species of biofuel crops in land that is not or can't be used for other production. In the flood-prone fields along the Missouri and Mississippi rivers, the crops are grown in huge trenches that will be flooded to simulate conditions.
The fields include 15 different varieties of each of the four candidate crops: willow, switchgrass, cottonwood and high-biomass sorghum. The researchers will compare how well they grow in different types of soil and under different amounts and duration of flood stress.
The results will reveal which varieties are likely to perform best in the floodplains. This knowledge will guide breeding programs to create new, improved varieties of biomass crops.
But, once the crops are grown, they need to be processed. Because raw biomass can contain up to 50 percent water, and therefore a lot of dead weight, transporting biomass could easily burn more fuel than would be created if conversion facilities are too far away. That would be bad for both the environment and the bottom line.
That's where the Show Me Energy Cooperative in Centerview, Mo., comes in. Facilities like the co-op's plant convert low-energy biomass into energy-dense products, including compact pellets that can be sold to power plants to generate electricity or to homeowners as a heating fuel. The plant is an example of what's called an advanced rural biorefinery, or ARBR, Jose said.
"This is a repeatable, replicable model that can be used anywhere in the U.S.," he said. "Farmers come together, form co-ops, grow biomass and convert that biomass into either pellets or any number of products that can be derived from that biomass, including liquid transportation fuels."
Establishing ARBRs along the river corridors could offer another advantage: Products could be shipped long distances on barges instead of trucks or trains.
"Barge traffic can be highly cost-effective," Jose said. "A 15-barge tow can replace 1,000 trucks on the highway."
A side benefit of a network of regional ARBRs is job creation and economic activity, he adds.
In addition to providing new sources of renewable energy, growing biomass crops offers other environmental benefits, often referred to as "ecosystem services."
For example, most of the candidate crops are perennials, which means you can plant them once and harvest every year for 10 or 15 years. This reduces the need to disturb the soil and apply fertilizers and herbicides, so these crops put much less sediment and chemical runoff into rivers and streams compared to crops like corn and soybeans. These plants also act as natural filters, trapping and breaking down chemicals in runoff from adjacent row-crop fields. Planting these in river floodplains means they're in an ideal location to intercept that runoff. The plants also provide valuable wildlife habitat.
As with fossil fuels, burning biofuels puts carbon dioxide into the air. However, that carbon dioxide was already in circulation until captured by the crops as they grew. Fossil fuels, on the other hand, add carbon that had been in the ground for millions of years.