As a young man I enjoyed science fiction books and movies portraying a future of fantastic flying cars, robots that would do all of your chores for you and Jetsonian conveniences. At my young age, those wild fantasies did not seem entirely outside of the realm of possibility in my long life ahead.
Since then, I have grown up and entered the professional world of agriculture and found a new flying car to wish for — cellulosic ethanol. Cellulose is considered the next frontier in ethanol production. The process involves extracting sugars from the cell walls of biomass from a wide potential range of plant materials.
Successful, large-scale corn-based ethanol, of course, has been a fairly recent, but successful addition to Ohio’s energy portfolio, though it is not without controversy. Right or wrong, livestock producers, consumer groups, and environmental groups have often been very critical of ethanol for a wide variety of reasons. One of the many counterpoints to the anti-ethanol argument is that corn ethanol serves as an economically viable bridge to better things in the future with cellulosic ethanol made from biomass.
This holy grail of bioenergy is often discussed and has even made its way into the Federal Government’s Renewable Fuels Standards (RFS) mandates. The RFS requires that 15 billion gallons of corn-based ethanol, 1 billion gallons of biodiesel and 16 billion gallons of cellulosic fuels be produced annually by 2022. According to a National Academy of Sciences study prepared for Congress, the corn ethanol numbers and biodiesel can be achieved, but the cellulosic goals probably cannot.
“There are conditions in which you could see us meeting the Renewable Fuel Standard for cellulosic biofuels, but they require major leaps in technology, substantial increases in oil prices and/or very large subsidies,” said Wally Tyner, from Purdue University, who co-chaired the committee for the National Academy of Sciences to produce the study.
The trouble with cellulosic ethanol production is that it is always 10 or 15 years down the road. Ten years ago the advent of successful cellulosic production was 10 years away. Now, with cellulosic fuel mandates looming, it still seems that commercially viable cellulosic production is 10 or 15 years down the road. We are perpetually “almost there” with cellulosic ethanol.
A collaborative effort of Universities around the country, including Ohio State and Purdue, has been working on research that will hopefully bring the industry closer to viable production of cellulosic ethanol. One viable source of biomass could be corn stover.
Corn stover’s pith, the soft core that makes up more than half the weight of a corn stalk, is the easiest for enzymes to digest, according to Michael Ladisch, director of Purdue’s Laboratory of Renewable Resources Engineering. The rind is the most difficult to digest, while leaves fall in between. Converting the rinds only adds about 20% more ethanol while requiring 10 times more enzymes, driving up the price of the process.
Separating pieces of corn stover and treating them differently would be a new way of approaching cellulosic ethanol production.
“It uses existing conversion technology, but it enables us to think about a new way of getting the most from that technology,” Ladisch said. “There is absolutely no reason a ligno-cellulosic non-food material such as corn stalk cannot be used to make ethanol if you understand the science.”
Purdue researchers are also looking at the viability of rapidly growing poplar trees as a potential feedstock for cellulosic production. The trees require less management and are capable of tremendous biomass production, but extracting sugar from cellulose is more difficult than it is with grain because of the presence of lignin.
With rising energy costs, economic woes and a spiking energy demand, I sincerely hope that we are able to meet the ambitious RFS cellulosic goals. With these ongoing research efforts, we may only be 10 or 15 years away from viable cellulosic production. And, by then, we can use this fuel source to power our robots and flying cars.