Photo credit: Dennis Schroeder / NREL
We all drive cars fueled in part by ethanol—a chemical compound and simple alcohol with the chemical formula C2H5OH that many consumers believe to be green energy. Ethanol, of course, comes mostly from corn, which in August grows as high as an elephant’s eye, a ubiquitous feature of the Wisconsin landscape.
The Renewable Fuel Standard (RFS) was passed in 2007 to incentivize green cellulosic fuels, made from non-food crops or crop waste. Between 2006 and 2012, tax credits and incentives for ethanol cost taxpayers an estimated $6-8 billion annually. Though designed to incentivize non-food crops, these credits and incentives went largely to subsidize corn and soy. Ethanol production was incentivized because it was viewed as a route to energy independence and a means to reduce greenhouse gas emissions.
Over time, the RFS has been criticized for not fulfilling its original promise. Recently, new research conducted by UW-Madison scientists found that cropland expansion from wetlands, pasture and forests released 115 metric tons of carbon between 2008 and 2012. During this period, more than 7 million acres of habitat were plowed under. During the same period, corn production for ethanol increased to satisfy the mandate and corn prices rose.
“This cropland expansion, driven in part by the ethanol mandate, has far-reaching impacts on the climate through its effects on the land and the carbon that it stores,” says Seth Spawn—lead author of the University of Wisconsin land use study and a graduate research assistant student at the Center for Sustainability and Global Environment at UW-Madison—adding that, “These impacts are significant and should be taken seriously.” Such increases in released carbon from the soil result in increased levels of carbon dioxide in the atmosphere, which contributes to the greenhouse effect.
Crops that Cause Pollution
Between 2008 and 2012, the amount of climate pollution from land conversion was calculated to be the equivalent of the annual emissions of 20 million additional cars on the road or six coal-burning power plants. In Wisconsin, annual emissions from Wisconsin cropland expansion were roughly equivalent to the annual emissions of 980,000 additional cars on the road, which roughly breaks down to an additional car for everyone living in Milwaukee County.
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While Wisconsin did not have the highest number of “cropland expansion” acres, the land that was converted in the state was particularly carbon rich, which resulted in high carbon emissions. Wisconsin was one of six states (along with North and South Dakota, Minnesota, Michigan and New York) where crop expansion occurred on carbon-rich forests and wetlands resulting in the highest per-acre emissions. These six states accounted for more than 35% of the total annual emissions from cropland expansion nationwide. First-generation biofuels came from starch-rich food plants—chiefly corn and soybeans—that are easily turned into ethanol. Although burning ethanol reduces greenhouse gas emissions, critics argue that the energy that goes into producing it neutralizes those benefits.
A Zero-Sum Game?
“The problem is that a lot of energy goes into growing those crops,” says Randall Jackson, professor of agronomy at UW-Madison and sustainability lead at the Great Lakes Bioenergy Research Center (GLBRC). “If you actually calculate the amount of energy it takes to make the fertilizer, plant the crops, make the gasoline to plant the crops and the carbon that it takes to make pesticides and herbicides to keep those crops as monocultures, the net energy gain hovers right around zero. Often it is negative, often it is positive, but it’s always right around zero ... It’s just a way to run our cars on natural gas and coal because that’s what goes into making all those products that make the grain that go into the gas tank.”
Jackson explains that there are two kinds of carbon. One is fossil carbon, which is stored below the ground. The other is new carbon, which is in the atmosphere and ecosystem. When plants grow, they take up new carbon from the atmosphere. “When we harvest them, turn them into ethanol and put it in our tanks, it goes back out into the atmosphere. So we’re just cycling new carbon,” Jackson says. “The problem occurs when we take old carbon from fossil fuels that we make petroleum out of now. We keep adding carbon to the atmosphere from the fossil fuels. So, long as we can use new carbon, that’s going to be better. The problem with first-generation ethanol is that to get that new carbon, we are still using old carbon.”
Despite the failures of first-generation biofuels, Jackson says that second-generation cellulosic biofuels hold great promise for the future. Cellulosic biofuels use the vegetative part of plants, not the grain, to make biofuel. “The real poster child for that is switch grass,” says Jackson. Also native and restored prairie plants and trees such as poplars can be used to make biofuel. “The promise of second-generation biofuels is primarily that those crops are low-input crops,” he says, “so they don’t take all the fertilizer and pesticides and herbicides. They can be perennial crops that don’t have to be planted year-after-year, so you don’t disturb the soil, and you don’t lose as much carbon.” Plowing and planting disturb the carbon sequestered in the soil and vegetation, releasing it into the atmosphere.
New Cost-Efficient Technology
The problem right now with second-generation cellulosic biofuels is that converting the cellulose into sugar—which then gets converted into ethanol—is not yet cost effective. But researchers like Jackson believe that cost-efficient technology to break down cellulose into sugar will be viable in the near future. His colleagues at the GLBRC have developed some promising new technologies.
One technology for breaking down cellulose is called Gamma-Valerolactone (GVL). James A. Dumesic, a professor in biological and chemical engineering at UW-Madison, developed this process. As Jackson explains, “GVL is a solvent that breaks down the biomass and turns it into basically the precursor of plastics and the precursor for lots of other products as well as fuel.”
A second technology is a process called Ammonia Fiber Expansion (AFEX). “This is just a process where the biomass is treated to pressure, which breaks apart the biomass and makes its three major constituents, lignin, cellulose and hemicellulose, separate. Then they smoosh it together to make little pellets,” Jackson explains. “The lignin sort of helps hold these little pellets together. The beauty of these pellets is that they’re the same size as a corn grain, and that helps overcome some of the problems with biomass, which is that it is big, white and fluffy; it’s not cost-effective to move it around. If you can pelletize and densify it, however, it solves a lot of the logistics problems of moving it around. Moreover, they’re doing feeding trials now, and they’re finding that these pellets are getting close to the nutritional quality of corn grain. In which case, if you can feed this stuff to livestock, convert it to biofuels or burn it as biomass, you’ve got this sort of dual use for the pellets. We see this as an opportunity to jump start things.”
Big Corn’s Opposition
Even though researchers appear to be on the brink of perfecting the technology to bring cost-effective and truly green second-generation biofuels forward, the forces in place against change are mighty. For example, almost 40% of the corn grown in Wisconsin is for ethanol production. In 2016, Wisconsin was the eighth-largest producer of grain corn. Grain corn is grown for non-food use, including animal feed, ethanol and corn oil. From 1997 to 2016, farmers in the U.S. have received almost $105 billion in federal subsidies to grow corn; Wisconsin’s share of that was nearly $5 billion. The value of Wisconsin’s total corn crop was almost $2 billion in 2016.
Between 2007 and 2013, the corn industry spent more than $158 million on lobbying and contributed more than $6 million to federal candidates between 2008 and 2014, according to Taxpayers for Common Sense. “I have no illusion that once it becomes economically feasible [to produce second-generation biofuels cost-effectively], the powers-that-be are going to work hard to quash it,” Jackson says. “I’m cynical enough in my old age to say that it’s up to our children. I’ve just been hell-bent on educating children about these fundamental changes we have to make. It’s going to take huge political courage. It’s going to take huge societal demand for clean energy or healthy food. Our farming is killing the Gulf of Mexico—the shrimp industry is getting absolutely hammered. Why are we willing to do this just so farmers can keep farming the way they always have here? It’s absurd.”
Jackson says second-generation crops like switch grass would help remove carbon from the atmosphere because they naturally store more carbon in their roots and in the soil. Corn doesn’t do that, and it also needs lots of water and nitrogen fertilizer, which ends up in lakes and rivers—a primary driver of algae blooms. Corn also requires bare soil, which causes soil erosion.
“Wouldn’t it be great if, as a society, we also paid farmers to grow [second-generation biofuel crops] because they stored more carbon in the roots?” Jackson asks. “We’ve got to pay farmers to grow switch grass. Even if it’s not as profitable on the market, we can help them by payments for what they do: payments for ecosystems services.”
Conservation groups such as the National Wildlife Federation and clean energy advocates such as the Clean Air Task Force oppose the ethanol subsidies for first-generation biocrops. Last month, the Trump administration renewed its commitment to the ethanol mandate—a victory for Big Corn but a defeat for conservationists and Big Oil (which also opposes the mandate because ethanol blending is cutting into the demand for oil).
Yet Jackson is cautiously optimistic about the future for second-generation biofuels. “We’re talking about transformational change. The stars have to align, and a lot of things have to come together all at once,” he says. “You do have the sense when you talk to farmers, that they’re ready to go; they just need the right price signals. We can make that happen. It feels like it’s right there,” Jackson adds. “But, of course, people are afraid of change.”
