Without question, finding alternative fuels for electricity production and transportation is one of the nation’s top priorities. Consider fossil fuels: a non-renewable source of cheap fuel, which has been burned in the past few decades as if it were going out of style. A growing number of politicians and scientists think that using fossil fuels is in fact “out of style” and believe we should employ “greener” fuels to meet our energy demands. One such alternative is waste biomass — the leftovers from forestry and agriculture practices — to produce a feedstock of simple sugars which can be converted into liquid fuel. The United States Department of Energy (DOE) thinks that biomass has high potential as an alternative fuel and has contributed significant funds for further research in the area. In fact a bill was passed late this summer which allocated money to create three bioenergy research centers.
"If we could accomplish [the process of deriving ethanol from biomass], the consumer would not even know the difference. What you pumped into the tank would just be gasoline or diesel; you would never know where it came from," Dumesic says.
Photo Credit: Matson ContardoUW-Madison is the central location for the Great Lakes Bioenergy Research Center (GLBRC). The other locations are Oak Ridge National Labs in Oak Ridge, Tennessee and the Lawrence Berkeley National Lab in Berkeley, California. Each center is a collaboration of universities, national laboratories and private-sector businesses, all working towards the common goal of bringing biomass-derived fuel from the lab bench to the gas pump. “The mission of the Great Lakes Bioenergy Research Center is grand but simple: we will remove bottlenecks that currently prevent us from realizing the promise of bioenergy as one way of reducing our dependency on fossil fuels,” Tim Donohue, UW-Madison professor of bacteriology, says.
Donohue is currently acting as the GLBRC director. Donohue’s role is to be a direct connection between partners within the agency and the DOE to ensure that the research priorities are aligned with the federal government’s objective, which is to convert plant biomass into liquid fuel. Donohue’s second role is to oversee the scientific aspect of all the partners and institutions involved in the GLBRC. He aims to ensure that everyone is working in a coordinated way to make the best use of each organization’s strengths. With so many entities contributing to this project, communication is critical. Good communication will ensure that technologies and resources are shared in a synergistic fashion to give this project its best shot at success.
The biggest hurdle in converting plant biomass to liquid fuel is the conversion of cellulose to simple sugars. Every year more than 1.3 billion tons of biomass cellulose is disposed of as waste. Cellulose is a polymer of sugars which is resistant to chemical, enzymatic and temperature degradation. This means that the compound cannot be readily broken down into its component simple sugars. According to Donohue, if a process was available to convert 1 billion tons of biomass cellulose into simple sugars, there would be enough feedstock for ethanol production to offset nearly 30 percent of imported petroleum-derived fuel.
The ethanol we use today comes from simple sugars in corn kernels. Therefore, the process of deriving ethanol leaves the corn cob and stalk as unusable biomass. One major goal of the GLBRC is to figure out how to break down cellulose, releasing the simple sugars to be used as the feedstock for liquid fuel. This will be accomplished either by breeding plants with a cellulose polymer, that is easier to degrade, or by deriving a new process that effectively breaks down cellulose.
“There is a lot of interest now to focus on ethanol as the end product, because we know how to make it. We have been making ethanol from sugars for hundreds of years. We make a lot of it in Milwaukee and in St. Louis,” Donohue says.
There are many groups on campus and around the country who are working to make the fermentation process more efficient on a large scale, but ethanol has intrinsic properties which make it a less-than-ideal transportation fuel. First, ethanol has a lower energy value than gasoline. This translates to fewer miles per gallon when used in automobiles. Also, ethanol is a polar molecule and readily dissolves in water. Water present in the fuel further degrades its energy value.
Dimethyl furan, or DMF, is used by the UW Catalysis Research Lab as a catalyst to convert simple sugars such as D-fructose into long-chain
Photo Credit: Matson ContardoWhile most of the biological communities work on producing ethanol, James Dumesic, UW-Madison professor of chemical and biological engineering, and his team in the catalyst community are looking at using catalysts for converting biomass to liquid fuel in forms other than ethanol. One such fuel that they’ve derived is dimethyl furan (DMF). This research was published in Nature on June 21 of this year. DMF is a molecule that is similar to ethanol in that it contains oxygen and can be used as a fuel additive; but it has a 40 percent higher energy content and is non-polar, so it separates from water.
Dumesic and his team are trying to develop a process that can convert biomass-derived simple sugars into liquid alkanes ranging in length from 7 to 15 carbon atoms — the same composition as premium sulfur-free diesel fuel or gasoline.
“If we could accomplish that process, the consumer would not even know the difference. What you pumped into the tank would just be gasoline or diesel, you would never know where it came from,” Dumesic says.
The fuel source would not need to be specified at the pump, as with other alternative fuels like E85, because the characteristics of the fuels would be exactly the same. This research has been proven in the lab and, at press time, results had been submitted for publication in Green Chemistry.
The technologies used in this conversion of biomass-derived sugar into gasoline or diesel are about five years out. According to Dumesic, the major hurdle is taking this process to large-scale production. The catalyst currently used in the lab is expensive, and there is no indication of its working lifetime. If the catalyst is able to last for a long time, its cost will not be much of an issue; however, if the catalyst becomes contaminated and needs to be changed frequently the cost will fall on the consumer and likely block this technology from taking hold in the market.
Having a petrol-like liquid fuel seems to be the direction in which we are inevitably headed. Reasons such as national security, energy independence and global climate change all weigh heavily, and the push for a diverse and sustainable energy portfolio is gaining momentum.
The future of biomass as a potential fuel source will dramatically influence rural landscape as production becomes commercial.
Photo Credit: Matson Contardo“In less than 100 years we have used a significant portion of fossil fuels which took millions of years to form, and we are going to run out of these fuels sooner than later,” Donohue says.
Since the year 2000, the U.S. has imported more than 12 billion barrels of oil. Numbers of oil barrels have been increasing for the past several decades. If we were to reach the bottom of the petroleum well or upset trade conditions, the U.S. as a nation would be in a very vulnerable position.
“From a state’s perspective we would like to reduce our dependence on energy that comes from outside the state. The people of Wisconsin would like to be a cost-neutral energy state. Given the amount of forestry and agricultural land, there is no reason that we should not be energy-independent and cost neutral,” Donohue says.
Furthermore, the scientific community seems to have reached the general consensus that we are in the midst of a massive global climate shift. Whether or not humans are the direct cause of this shift still sparks debate, but our means of producing power and fueling transportation do emit significant amounts of carbon dioxide, a known greenhouse gas.
“What we have done…is put a lot of old carbon into the atmosphere. As we start to use plant material, we are also going to be converting that into carbon, but it will be new carbon which was fixed in the last year’s growing cycle,” Donahue says.
By relying on biomass-derived fuel, we will theoretically reduce the amount of old carbon released into the atmosphere, potentially stifling the negative effect burning fossil fuels has on the atmosphere.
Tim Donohue, GLBRC director and professor of bacteriology at UW-Madison.
Photo Credit: Matson ContardoThe GLBRC will consider technologies which are economically viable and environmentally sustainable. Both aspects are of equal importance.
“We are very interested in developing technologies which will work on the land in the long run. We do not want to produce new breeds of plants or new agriculture practices that prevent the land from being able to sustain farming because then we will have created a larger problem than we have solved,” Donohue says.
There are many issues to consider before rolling out technologies such as those that the GLRBC will generate. Also, scaling the technologies to the level which will be needed to make up a significant portion of our liquid fuel demand will be complicated. There is an inevitable give-and-take relationship between energy production and the environment, and careful thought and foresight must be used with any new technology.
“The DOE realizes that we are embarking on a long-term mission. Like the mission we embarked on in the 60’s to send a man to the moon and in the 80’s when we said we wanted to sequence the human genome—we are part of a grand scientific mission,” Donahue says.
It is understood that this is a massive undertaking and the DOE does not expect to see an immediate solution. They do, however, expect that the funds provided will produce certain deliverable products and processes which will aid the cause. The DOE will evaluate the progress of the GLBRC based on yearly deliverables, at which point they will determine the subsequent year’s funding. These are critical to the future of the GLBRC as they will be a way for elected officials to see what the program has accomplished and where it is headed. This is a large investment and there is no way politicians can micromanage the center. Deliverables will give the annual feedback needed for politicians to justify the cost to their taxpaying constituents.
Through the joint effort of many people working towards a secure and sustainable energy future, it is not hard to imagine that the wasteful consumption of fossil fuels will be soon out of style and a thing of the past.
“For every gallon of fossil fuels we don’t use, that is one less gallon we have to worry about replacing,” Donohue says.