Fuel, Sweet Fuel

Author:  Dunia Rassy
Institution:  London School of Hygiene and Tropical Medicine
Date:  October 2008

A couple of announcements made this month by independent teams will have us realize that green gasoline is not anymore an ambitious goal, but rather a reality. Through the conversion of plant sugars, scientists have been able to obtain a high-energy liquid, similar to petroleum, which can be likewise processed to yield all kinds of fuels and raw materials for pharmaceutical and chemical industries.

The teams led by Randy Cotright, at Virent Energy Systems, and James Dumesic of the University of Wisconsin at Madison, achieved the transformation using what they dubbed an "aqueous phase reforming process". A watery mixture of plant-derived sugars and carbohydrates passes over a series of catalysts (compounds which accelerate reactions without being used up). These catalysts allow sugar molecules to return into their basic elements. Later on, elements combine again during an intermediate stage to form an organic liquid made up of functional compounds. Specific chemicals can then be isolated just the way it is done with petroleum and upgraded to produce fuels.

Ecologically speaking, the sugary liquid obtained poses several advantages above other proposed fuels. The aqueous phase reforming process can employ sugars from agricultural waste such as corn stover, sugarcane bagasse, wood chips, plants grown in marginal soil, or possibly even paper. Since plant sugars are produced by photosynthesis, which depends on solar energy and carbon dioxide, burning fuels based on these sugars would mean returning the same amount of carbon dioxide to the atmosphere. Diminishing our carbon dioxide emissions would help alleviate greenhouse gas effects and perhaps global warming.

Even when we have witnessed impressive development of alternative energy sources, most of them are not energetic enough to drive our daily needs. "We will still need high energy-density gasoline, diesel and jet fuel for planes, trains, trucks, and boats. The processes that these teams developed are superb examples of pathways that will enable the sustainable production of these fuels." added John Regalbutto from the National Science Foundation, which funded both groups. Compared to other solutions, green gasoline is very close in its net energy yield to current available fuels and does not take up crops intended for human consumption, and because it is compatible with the existing infrastructure, its commercialization and availability will seem feasible before long.

Five to ten years will be needed to refine the process and scale it up for production; nonetheless, it has received broad industrial interest. Virent Energy Systems recently allied with one of the world's largest energy companies in an attempt to bring their alternative fuel to market. Investments from major automotive and agricultural companies are pushing forward Virent's efforts as can be appreciated by Cotright's statement: "We are quickly working to put our renewable green gasoline.in fuel tanks all over the world."

Written by: Dunia Rassy

Edited by: Jeff Kost

Published by: Hoi See Tsao