Powering up with poop and plants

by Stewart McCoy

During the 1970s, a strange but brilliant Englishman by the name of Harold Bate invented a conversion process that fueled his car on chicken droppings. He engineered a carburetor attachment that allows any kind of car to run on methane. In his day, he paid the equivalent of $.03 per gallon for fuel. Bate powered both his car and 5-ton truck with methane, and even heated his farm houses. He wasn’t a quack either—his process was officially recognized by the British Ministry of Transport. In modern terms, Bate’s car ran on biogas, which is one kind of biofuel.

An uncertain future

With gas prices now hovering between $3 and $4 per gallon in the United States, researchers are scrambling to refine biofuels and make them competitive on the mass market.

Biofuels are forms of alternative energy derived from sources as diverse as landfill garbage and discarded corn cobs. Any carbon source will do. Currently, however, most mass-market biofuels—particularly ethanol and biodiesel—run on grains from plant sources such as corn and soybeans. These “first generation” biofuels aren’t cost competitive because they are more expensive to produce than regular gasoline and diesel.

Despite such expenses, advocates champion biofuels as the sustainable alternative to power our vehicles and meet the energy needs of our future. A multitude of reports conclude that biofuels have the potential to cut man-made greenhouse gas emissions and reduce or eliminate the impact of global warming. What’s more, it’s believed they reduce incidents of cancer or pollutants that result in smog and respiratory diseases.

So, if biofuels are so great, why aren’t they replacing fossil fuels as our primary energy source? Part of the problem is supply. Most ethanol in the United States is produced from fermented corn sugars. Corn is an integral part of our food supply, so any product diverted to fuel production (using current methods) contributes to increased food prices.

Also a problem is our current infrastructure. Today’s cars can only run on about 10 percent ethanol blended with regular gasoline. This means the benefits of ethanol become negligible—our cars will continue running on an energy source that, besides polluting our air, will eventually run out.

These concerns are part of a more complicated and interconnected biofuels lifecycle than typically presented by supporters, according to Dr. David Tilman, Department of Ecology, Evolution, and Behavior and Dr. Jason Hill, Department of Applied Economics, both at the University of Minnesota.

In an interview with Scott Simon, National Public Radio, Tilman reports:

“It takes a lot of energy to grow corn. And it takes even more energy to convert that corn into ethanol. By the time we’re done, if you look at the total energy in a gallon of ethanol, only 20% of that is new energy; 80% of that is a fossil energy we had to use to grow the corn and make that fuel. That’s not much of a gain. If you look across the whole lifecycle of growing corn, making ethanol, and burning it in a car, and compare that to what happens when you find oil, make gasoline, and burn it in a car, you only have about 15% less greenhouse gas going into the air from burning ethanol than you would if you burned gasoline.”

This consideration means that priority needs to be given to “second-generation” biofuels, which are fuels that have lower inputs of fossil fuels, use both the seed and the biomass, and use that biomass to power ethanol production plants. Biomass includes plant waste and energy crops such as

• Corn stover (leftover cobs, husks, and leaves)
• Wood chips
• Sorghum
• Miscanthus
• Switchgrass
• Hemp
• Poplar
• Willow
• Sugarcane
• Trees such as eucalyptus and palm

According to Tilman, these resources, combined with sustainable production methods, will result in fuels that could give us 80% or 90% reductions in greenhouse gases.

Still, Tilman reminds us that even with such advances, biofuels would only meet 10–20% of global energy needs, and that energy conservation will have to become an everyday part of life.

The next generation of biofuels

In the meantime, however, if Harold Bate could get his car to run on chicken poop, surely multi-billion dollar corporations can fund research to get cars running on sustainable energy sources like biomass.

At 80–90% carbon savings, second-generation fuels seem more like common sense than genius. Instead of using the grain from corn, why not use left over material, like the husk and cob?

Well, there are lots of variables involved. That’s why researchers are trying to figure out an efficient, safe, and inexpensive way to break down biomass, which is more difficult to process than grains.

What they need to do is develop a way to break down the cell walls of plants and separate the sugars into alcohol. This can be accomplished either by combustion or fermentation. During combustion, organic matter is turned into fuel through burning. Fermentation, on the other hand, breaks down organic matter by introducing yeasts to convert sugars to energy in the absence of oxygen.

I mentioned variables. Researchers need to consider which crops are best-suited for biomass-to-fuel conversion and have the smallest impact on the environment. For instance, corn stover is effectively a fertilizer, returning important nutrients to the soil. Stover also prevents erosion during the winter. If corn stover is to be harvested to make biofuel, then there needs to be another way to maintain soil fertility and prevent erosion.

Another variable is biomass density. The energy that can be generated from a harvest of switchgrass versus corn is not the same per acre. Switchgrass requires more land to generate the same amount energy that corn can grow on less land.

If researchers are able to address and resolve these kinds of variables, then we could have a more sustainable and more commercially viable energy resource. As long as the sun sticks around and plants continue to convert light energy into chemical energy, then we won’t need to worry about that resource running out like fossil fuels.

Proceed with caution!

Despite all the possibilities that biofuels present for a sustainable energy future, there are guidelines that need to be followed. These energy resources all claim they can potentially reduce greenhouse gases and pollutants, but the keyword is potentially.

Imagine a future where biofuels become more than a marginal energy source. More people will be driving cars powered by biomass. If additional land is converted to produce these feedstocks, then biofuels could actually end up being greater emitters of greenhouse gases than fossil fuels, according to Joseph Farigone of The Nature Conservancy.

Calculating the carbon savings of biofuels in terms of their production is complex. In a report on this subject, Farigone explains that plants are essentially carbon storehouses that keep greenhouse gases from entering the atmosphere. So if land not previously used for farming is cleared and plants are destroyed, then all those carbon storehouses end up back in the atmosphere.

The report concludes that the best way to grow energy crops and gain the benefit of reduced greenhouse gases is to use abandoned agricultural lands planted with perennials—crops that don’t have to be replanted every year.

Farigone, Tilman, and Hill all agree: efficiency and conservation need to be the focus of sustainable energy development. Bate, too, thought efficiency and conservation were important. He powered his car with resources from his own backyard, in this case, chicken poop. He didn’t let waste go to waste.

Looking for a job?

The biofuels industry has seen continual growth during the last decade, and there are plenty of career opportunities . Most individuals work as engineers, agronomists, chemists, and lab technicians.

Engineering side of biofuels

For those interested in the engineering side of biofuel development, the Department of Agriculture and Biosystems Engineering at Iowa State University offers courses in biorenewable and biofuels products and processes. For more information visit http://www.abe.iastate.edu/academics/majors-and-programs.html.

Iowa State also offers a major in agronomy. Students can focus on the development of bioenergy. For those specifically interested in biofuels, training is available in genetics and plant breeding to develop crops specifically for fuel production. For more information, visit the Department of Agronomy’s website: http://www.agron.iastate.edu. 

Hands-on training in biofuels

Are you more interested in hands-on work and training that will prepare you to go straight to work as a technician? Indian Hills Community College and Iowa Lakes Community College offer programs in biorenewable fuels technology. For more information, read this month’s “School spotlight” department.

Editor’s note
Ethanol is a term that refers to products resulting from 2 different types of alcohol refinement. The first kind of ethanol can be made synthetically by refining petroleum. The second kind of ethanol is called “bioethanol” in the biofuels industry. It’s made by fermenting sugars with yeast and is the type of ethanol discussed in this article.