Friday, May 18, 2007

Peak Oil: Meet Biofuels

The entire transportation infrastructure is based on combustion engines. Combustion engines feature very high energy density combined with very high power density. Such a combination is difficult to achieve with electric storage and fuel cell technologies. So it is natural that a lot of venture capital is being invested in the development of liquid biofuels, to substitute for fossil fuels currently used in the transportation industry.

Biodiesel, cellulosic butanol, and now pyrolytic liquid biofuels offer a renewable way to ease the transition from a fossil fuel based infrastructure to an eventual combustion-free transportation and energy infrastructure.
A team of University of Georgia researchers has developed a new biofuel derived from wood chips. Unlike previous fuels derived from wood, the new and still unnamed fuel can be blended with biodiesel and petroleum diesel to power conventional engines.

“The exciting thing about our method is that it is very easy to do,” said Tom Adams, director of the UGA Faculty of Engineering outreach service. “We expect to reduce the price of producing fuels from biomass dramatically with this technique.”

Adams, whose findings are detailed in the early online edition of the American Chemical Society journal Energy and Fuels, explained that scientists have long been able to derive oils from wood, but they had been unable to process it effectively or inexpensively so that it can be used in conventional engines. The researchers have developed a new chemical process, which they are working to patent, that inexpensively treats the oil so that it can be used in unmodified diesel engines or blended with biodiesel and petroleum diesel.

Here’s how the process works: Wood chips and pellets – roughly a quarter inch in diameter and six-tenths of an inch long – are heated in the absence of oxygen at a high temperature, a process known as pyrolysis. Up to a third of the dry weight of the wood becomes charcoal, while the rest becomes a gas. Most of this gas is condensed into a liquid bio-oil and chemically treated. When the process is complete, about 34 percent of the bio-oil (or 15 to 17 percent of the dry weight of the wood) can be used to power engines. The researchers are currently working to improve the process to derive even more oil from the wood.

Many scientists have opposed biofuels as being inefficient and potentially harmful to the public health. The facts of transportation and energy/heating suggest that petroleum based fuels will trend progressively higher over time, as long as there is no significant recession or depression in the world economy. Given these rising costs, one would expect the smart money to invest in ways to produce useful fuels less expensive than future fossil fuels will be.

Many science bloggers have suggested that biofuels are a dead-end for the future. They say that the costs of producing the fuel are as great as the value of the fuel itself. They suggest that there is not enough land to grow both biofuels and food crops.

These are interesting claims, but they are unlikely to hold up in the face of the economic importance of viable alternatives to fossil fuels that can be used with existing combustion equipment, and such equipment as is likely to be introduced in the near term.

Food crops can be grown economically using aeroponic techniques, in the driest deserts, in outer space, or on sea-floating arcologies. Human ingenuity in the growing of both food crops and biofuel crops has just barely been tapped. The importance of liquid fuels in the trillion dollar infrastructures suggest that liquid biofuels will be very important quite soon, and for at least several decades.

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