The technology is not quite competitive - barrel for barrel or ton for ton - with existing energy sources, but if all the secondary costs and benefits (transportation, waste disposal, pollution and disease control, compatibility with existing energy infrastructure, vulnerability to terrorism, etc.) were factored in, it would look more competitive than other energy alternatives:

The process is designed to handle almost any waste product imaginable, including turkey offal, tires, plastic bottles, harbor-dredged muck, old computers, municipal garbage, cornstalks, paper-pulp effluent, infectious medical waste, oil-refinery residues, even biological weapons such as anthrax spores. . . . Unlike other solid-to-liquid-fuel processes such as cornstarch into ethanol, this one will accept almost any carbon-based feedstock. If a 175-pound man fell into one end, he would come out the other end as 38 pounds of oil, 7 pounds of gas, and 7 pounds of minerals, as well as 123 pounds of sterilized water. While no one plans to put people into a thermal depolymerization machine, an intimate human creation could become a prime feedstock. "There is no reason why we can't turn sewage, including human excrement, into a glorious oil," says engineer Terry Adams, a project consultant. So the city of Philadelphia is in discussion with Changing World Technologies to begin doing exactly that. "The potential is unbelievable," says Michael Roberts, a senior chemical engineer for the Gas Technology Institute, an energy research group. "You're not only cleaning up waste; you're talking about distributed generation of oil all over the world."

. . . a large chunk of the world's agricultural, industrial, and municipal waste may someday go into thermal depolymerization machines scattered all over the globe. If the process works as well as its creators claim, not only would most toxic waste problems become history, so would imported oil. Just converting all the U.S. agricultural waste into oil and gas would yield the energy equivalent of 4 billion barrels of oil annually. In 2001 the United States imported 4.2 billion barrels of oil.

. . . the process can be tweaked to make other specialty chemicals that may be even more profitable than oil. Turkey offal, for example, can be used to produce fatty acids for soap, tires, paints, and lubricants. Polyvinyl chloride, or PVC�the stuff of house siding, wallpapers, and plastic pipes�yields hydrochloric acid, a relatively benign and industrially valuable chemical used to make cleaners and solvents. "That's what's so great about making water a friend," says [CWT CEO Brian] Appel. "The hydrogen in water combines with the chlorine in PVC to make it safe. If you burn PVC [in a municipal-waste incinerator], you get dioxin�very toxic." . . . Appel picks up a handful of one-gallon plastic bags sent by a potential customer in Japan. The first is full of ground-up appliances, each piece no larger than a pea. "Put a computer and a refrigerator into a grinder, and that's what you get," he says, shaking the bag. "It's PVC, wood, fiberglass, metal, just a mess of different things. This process handles mixed waste beautifully."

. . . "The only thing this process can't handle is nuclear waste," Appel says. "If it contains carbon, we can do it."

. . . "This plant will make 10 tons of gas per day, which will go back into the system to make heat to power the system," he says. "It will make 21,000 gallons of water, which will be clean enough to discharge into a municipal sewage system. Pathological vectors will be completely gone. It will make 11 tons of minerals and 600 barrels of oil, high-quality stuff, the same specs as a number two heating oil . . . The Environmental Protection Agency doesn't even consider us waste handlers. We are actually manufacturers�that's what our permit says. This process changes the whole industrial equation. Waste goes from a cost to a profit." [Emphasis mine - JSW ]

From the FAQ for the Carthage MO plant: The only by-product is processed water.

TDP is almost commercially viable in the US. Two factors that could bring in more customers are rising oil prices and more livestock regulation in response to BSE.

The initial estimate of the cost of the oil from the Missouri plant is $15 (�9) a barrel. The "lifting" price - how much it costs to get oil out of the ground - is very cheap in the Persian Gulf, around a dollar a barrel, while from Gulf of Mexico, North Sea or Alaska the "lifting" price is $8-12. So a price of $15 a barrel for this technology is high but Appel predicts his prices will come down to $10 in a few years, making them comparable with a medium-size oil exploration and production company. "The oil that comes out is very light," says Appel. "It is essentially the same mix as half fuel oil, half gasoline."

Factor in lower refining and transportation costs to subtract from the "lifting price" of TDP-generated oil. TDP plants can be built anywhere, of any size, with off-the-shelf components. They can be built right next to both their sources of raw material and the customers for the end products, resulting in far fewer oil tankers to break up in heavy seas, run aground, or become terrorist targets.

At this point in the US it is more profitable for livestock operations to sell their wastes to make livestock feed, but fear of disease could change that as it already has in Europe.

Since [the case of mad cow disease in Washington state], interest in using thermal conversion to control the disease has skyrocketed, say company officials. Although no testing has been done on the effect of the thermal conversion process on prions, the rogue proteins that are thought to cause BSE, [MIT chemical engineering professor Jefferson] Tester is confident that the high pressures and temperatures it uses would be more than sufficient to dismantle those pathogens. �Large molecules like that really don�t like that kind of environment,� he says.

Appel says the Colorado plant will be designed to digest whole, diseased cattle along with slaughterhouse waste. �Americans are finally realizing what the Europeans and others have figured out�there are high risks associated with intense farming practices� that involve feeding rendered animals back to animals. �We will divert proteins away from the food chain. You�ll see less disease and less bioaccumulation of toxins when animals once again start eating grass and grain, the way they were meant to eat.�

Even existing energy producers don't view TDP as a threat, because they can use it to make their products cleaner and more efficient and to extract other commercial materials.

Experiments at the Philadelphia thermal depolymerization plant have converted heavy crude oil, shale, and tar sands into light oils, gases, and graphite-type carbon. "When you refine petroleum, you end up with a heavy solid-waste product that's a big problem . . . This technology will convert these waste materials into natural gas, oil, and carbon. It will fit right into the existing infrastructure."

Appel says a modified version of thermal depolymerization could be used to inject steam into underground tar-sand deposits and then refine them into light oils at the surface, making this abundant, difficult-to-access resource far more available. But the coal industry may become thermal depolymerization's biggest fossil-fuel beneficiary. . . . experiments show the process can extract sulfur, mercury, naphtha, and olefins - all salable commodities - from coal, making it burn hotter and cleaner. Pretreating with thermal depolymerization also makes coal more friable, so less energy is needed to crush it before combustion in electricity-generating plants.

No, it wouldn't completely replace current energy sources, but it could make a huge dent in global dependence on Arab oil and solve troublesome recycling problems at the same time.

More here, with a follow-up discussion here.

UPDATE: Some caveats, and a response, here.