To our knowledge the biggest operator in the USA of commercial scale plants that create fuel from animal waste is Changing World Technologies, headquartered in West Hempstead, New York. This company has a plant in Carthage, Missouri, that in April 2006 produced 6,000 barrels of diesel fuel. The plant uses turkey offal as the feedstock, in a joint venture with Conagra’s massive Butterball turkey processing plant.
Today I had the opportunity to talk with Brian Appel, Chairman of Changing World Technologies, and I asked him whether or not this plant was continuing to produce at that volume. Appel declined to provide recent production figures but confirmed that the plant was operating normally and that 6,000 barrels per month was less than full capacity. The Carthage facility is a commercial scale pilot plant producing fuel from waste, and it is the largest of its kind currently in the United States.
Changing World Technologies also has a pilot plant getting started in Philadelphia, processing shredder residue from recycled automobiles. In this case, the plant is recovering the metals from the cars, as well as recovering oil from the plastics that were in the car. This plant is also the first of its kind in the U.S.
Thermal depolymerization is a method used to separate long molecular chains into shorter ones, using water and heat inputs. It is a fairly complex process that has only recently evolved to the point where it can become commercially viable, and only within the last 20 years had the technology evolved to the point where it is an energy-positive process. For much more on thermal depolymerization, go to the “what” page on Changing World Tech’s website, or go to the “thermal depolymerization” entry in Wikipedia.
There are several ways to analyse the potential of thermal depolymerization. First of all, how much feedstock is there? There are approximately 12 billion tons of solid waste produced in the USA each year, about 50% of that is agriculture, and most of the rest is municipal (land fill). Claims that 100% of this waste can be converted to fuel are open to debate, to say the least, but the point is that this material is waste – if any of this waste can be converted to fuel at a price competitive to petroleum, it should be.
Another interesting point relating to thermal depolymerization is the potential this technology may have towards helping advance the refining of cellulose to produce fuel. While the primary extraction of ethanol and diesel from food (sugar cane, corn) is a fairly well understood process, already commercially competitive in many countries, the process to convert the waste material – sawdust, crop residue, grass – is not there yet. Currently there is not a single commercial scale cellulosic ethanol refinery in the world, yet cellulose, the waste from plants, is far more abundant and would not undermine or compete with crop production for food.