A New Twist on Using Wood for Fuel
by Jeremy Elton Jacquot, Los Angeles on 05.19.07
The notion of using wood as a source of energy is hardly a new or revolutionary one. At a time when scientists and businesses are increasingly relying on an eclectic and innovative array of alternative energy sources, including palm oil, corn and cellulosic ethanol for fuel and plant sap, apple juice and urine for batteries, turning to a material whose use as an energy source was pioneered by our distant forbears seems odd. Yet, disproving the convention that you can't teach an old dog new tricks, a team of researchers at the University of Georgia has created a new biofuel derived from wood chips that can be mixed in with biodiesel and and petroleum diesel to power conventional engines.
While scientists have long held the ability of deriving oils from wood, they had until now not found a cost-effective way of processing it into a form that could be used in engines. To resolve this issue, researchers at UGA came up with a new chemical process that consists of first burning wood chips and pellets in the absence of oxygen at a high temperature, a process known as pyrolysis, and then condensing the gas that arises as a result of this initial step into a liquid bio-oil that is chemically treated. Approximately 34 percent of the bio-oil derived from the wood can be used to power engines while the charcoal that also arises from the pyrolysis step, known as "carbon char", could potentially be used as fertilizer.
Another benefit of this process is that it produces a fuel that is nearly carbon neutral, meaning that it doesn't significantly increase greenhouse gas levels in the atmosphere as long as new trees are planted to replace those used to make the fuel. If the charcoal that is also produced in the process proves viable as a source of fertilizer, Adams argues that the biofuel would actually be carbon negative.
“You’re taking carbon out of the atmosphere when you grow a plant, and if you don’t use all of that carbon and return some of it to the soil in an inert form, you’re actually decreasing the amount of carbon dioxide in the atmosphere,” Adams explained. “We’re optimistic because in most types of soil, carbon char has very beneficial effects on the ecology of the soil, its productivity and its ability to maintain fertility.”