Complications Lurk Behind Surging Interest in Biofuels, Land-Use Expert Says

Louise Chini was bumping down a dirt road in a rented SUV, searching for tall plants amid fallow farmland when the vehicle suddenly veered into a weed-obscured ditch. The resident farmer kindly used a tractor and chain to extricate the University of Maryland associate research professor of geographical sciences, who after her rescue posed a question: Was there any switchgrass nearby? 

The farmer responded that he’d turned his Northwest Pennsylvania cornfield into a switchgrass field in recent years and sold his latest crop to a seed producer. His answer told Chini, who studies land-use modeling and climate mitigation, all she needed to know during that trip two summers ago: Switchgrass was not only being cultivated in this region as a possible energy source, but it was displacing crops mainly grown for food. 

The current blockade of the Strait of Hormuz is prompting oil-dependent nations to look increasingly to biofuels like ethanol and biodiesel. While the biofuel industry’s focus has traditionally been on food crops like corn or beans, scientists have more recently looked to “second-generation” biofuels that come from other vegetation in hopes of protecting global food supplies.

Farmers like the one Chini met in Pennsylvania have begun selling the fiber-rich switchgrass plant, native to the United States, as a raw ingredient for ethanol. Because switchgrass isn’t a food crop and evidence suggests it can be harvested on relatively unfertile ground, it will have less impact on nutrition around the world, supporters argue.

Chini, however, isn’t so sure switchgrass doesn’t present a food vs. fuel tradeoff, or that it won’t have other unpredictable consequences. The professor, who developed the land-use dataset used by the world's climate projection models, noted that no reliable methodology exists to prove switchgrass’ large-scale benefits. “You have to wonder if it’s replacing other land-use types and how that would play out long-term,” she said.

Chini sat down with Maryland Today to discuss her current project, funded by a UMD Grand Challenges Grant, to create a standardized switchgrass monitoring system (while hopefully avoiding more ditches).

Why should we care about biofuels?
Second-generation bioenergy crops like switchgrass can be used for sustainable aviation fuels and for industrial power and heat generation, diversifying our energy economy, while also reducing atmospheric carbon dioxide concentrations with decarbonization technology. Climate change mitigation is one of the biggest challenges of our time and switchgrass could provide a new option in our toolkit for climate action.

Yet you’re a skeptic?
Yes. Growing crops require farmers, so the idea that second-generation crops don’t need to be grown on agricultural land is unlikely, and developing industrial-scale refineries is a huge investment. There’s already a lot of pressure on the land to do too many things. 

Why study switchgrass in particular?
I was alarmed by how many existing models thought we should grow it at a large scale because there wasn’t much discussion about unintended consequences. Would it compete with food crops? Require a huge amount of irrigation that could drain our water supply? Is there a biodiversity impact? To understand how much that’s happening, we need a way to monitor it with remote sensing data. Our Grand Challenge project is to map and monitor it, to see the land-use types they’d be replacing.  

What have you learned?
We saw quickly a switchgrass information gap. Data from the U.S. Department of Agriculture is sparse and shielded for privacy reasons. Some public data comes from farmers, but there’s no universal methodology for measuring and reporting it so there could be errors. 

The data we did find showed Crawford County, Pennsylvania, as a hotspot based on 1-year-old images. So a student and I spent a day driving around to verify it. We arrived at a farm we thought would be full of switchgrass, but it was bare. That’s when the farmer and his wife—lovely people—said they’d sold their recent crop. The farmer said the whole region was big into switchgrass, alternating its cultivation with food crops like corn. 

Where does the study stand?
After we confirmed the presence of switchgrass, Elda Bezuayene, a Ph.D. student in the Department of Geographical Sciences, used a remote-sensing model with NASA data to distinguish it from other crops, which she accomplished by studying different wavelengths. It’s very tall—I’m 6 feet, and it’s taller than me—and very sharp; if I walked through a field it would cut through my shoes.

Now with our model we can monitor changes to a switchgrass field in a standardized way. The next step is to expand it across the country.