TOPICS:Alcohol fuels | Biodiesel | Biogas | Other liquid fuels

Unlike other renewable energy sources (solar, wind, geothermal, hydroelectric), biomass can be converted directly into liquid fuels, called biofuels. These fuels will help meet the rising demand for transportation fuels of the nation. The two most common types of biofuels are ethanol and biodiesel.

Biodiesel is made by reacting alcohol (usually methanol) with vegetable oil, animal fat, or recycled cooking grease. Biodiesel contains no petroleum, but it can be blended at any level with petroleum diesel to create a biodiesel blend. It can be used in compression-ignition (diesel) engines with little or no modifications. Biodiesel is simple to use, biodegradable, nontoxic, and essentially free of sulfur and aromatics. Biodiesel is made through a chemical process called transesterification which produces methyl esters (biodiesel) and a byproduct of glycerine.

Alcohol fuels are made by processing any biomass high in carbohydrates through fermentation. Today, ethanol is made mainly from starches and sugars; however, researchers are working on near-term technologies to allow it to be produced from cellulose and hemicellulose, the fibrous material that makes up the bulk of most plant matter. Ethanol is currently used in many parts of the country as a fuel additive (at 2% concentration) as an oxygenate. This increases octane and cuts down carbon monoxide and other smog-causing emissions. Ethanol is becoming more widely used as a fuel supplement at higher concentrations like E-10 (10%) and E-85 (85%). As these blends become more popular throughout the country, ethanol will be able to displace a sizeable percentage of the gasoline used across the nation.


Brian Bibens and K.C. Das check the process of the continuous pyrolysis machine. They will use pyrolysis to turn coarse particles of chicken litter into char and bio-oil.

Jimmy Palmer of the EPA, right, presents a grant to (left to right) Sid Thompson, K.C. Das, Kaushlendra Singh, Mark Risse and John Worley of UGA's Department of Engineering.

From Environmental Report 2007
College of Agricultural and Environmental Sciences
By Stephanie Schupska

Two and a half pounds of litter is about how much one chicken produces in its lifetime. A team of University of Georgia scientists is working to turn the poultry state's waste litter into a valuable alternative fuel product. That's good news in Georgia, where chickens, specifically broilers, rank no. 1 in the state's agriculture, with a leaving-the-farm value of almost $4 billion. Poultry litter is mostly manure mixed with a bedding material such as wood shavings.

Two and a half pounds of litter per broiler is 2.5 pounds of by-product waiting to be converted into something usable, said Jimmy Palmer of the U.S. Environmental Protection Agency. With funding from an EPA grant, UGA researchers are searching for ways to add value to poultry waste.

"This will help us collectively deal with environmental issues of growing agriculture," said Palmer, an EPA regional administrator.

"A waste is a terrible thing to mind," he said, twisting a common phrase. "We're looking for better ways to deal with waste."

Through a process called fractionation, UGA researchers plan to produce two types of materials from the poultry litter, separating the fine and coarse parts, said Mark Risse, a UGA Cooperative Extension engineer and member of the research team.

The scientists form the fine, nutrient-rich material into pellets for fertilizer. Because the processed fertilizer pellets would allow a slower release of nutrients into the soil, pollution from pathogens and nutrients in the poultry litter would be reduced.

"Most poultry litter is currently being directly landapplied as fertilizer," said K.C. Das, coordinator of the UGA Biorefinery. "it makes sense to a point. But in north Georgia, there's not enough land to spread the litter. Through this process, we're producing a better energy product as well as a better fertilizer."

The research team puts the coarse, energy-rich poultry litter material through an intense heating process called pyrolysis to create char and bio-oil. The char can be used anywhere charcoal is used. Bio-oil can be refined further and used as diesel-like fuel.

UGA engineers say developing a cheap source of energy from poultry litter would provide a cleaner source of energy, helping the state grow in an economically and environmentally sustainable way. They estimate that in the United States, using poultry litter as fuel could save 283 million gallons of fossil fuel.

"Two or three companies are looking at Georgia right now," Risse said. "They're looking at pelleting litter for fertilizer. There's a very real opportunity for research that can be used not 10 years from now, but now."

"A lot more is said than usually done, and we're about to do it," Palmer said of the project.

Besides Risse and Das, the UGA research team includes Cooperative Extension engineer John Worley, professor Sid Thompson and graduate student Kaushlendra Singh.

The project builds on work Thompson did 15 years ago and had to shelve due to a lack of application at the time. now, with the demand for alternative fuels increasing, his halted research can continue.

The project team is in the process of showing they can break up poultry litter into two parts and use both. The researchers will also have to determine whether the processes should be done at centralized locations across the state or at individual farms.

"Poultry litter represents two times the energy consumption on a farm," Das said. "You have everything you need to produce energy on the farm already."

Stephanie Schupska is a news editor with the University of Georgia College of Agricultural and Environmental Sciences.