By: Tina Casey
The laundry list of sustainable biofuel crops just keeps getting longer and longer, thanks to new research that shows how to break down the hard cell walls of woody, non-food plants like switchgrass. Now researchers at North Carolina State University have revamped the woody biofuel production process itself to cut down on waste and practically eliminate the use of harsh chemicals.
In just a few short years, the biofuel industry has done a great job of digging itself out from under the misguided (but what else would you expect?) national policy of the past administration, which focused on corn and other food crops. The rapid development of more sustainable biofuel crops and processes is clear evidence that the era of high-risk fossil fuel harvesting could come quickly, and thankfully, to a close with help from a strong national sustainable energy policy that supports biofuels along with solar, wind, and other low risk methods of harvesting energy.
Better Crops for Biofuel
The biofueld industry has begun to focus on weedy biofuel crops like crambe because they do not compete for space with food crops. They can be grown as part of a crop rotation plan or grown on marginal lands, including former industrial sites and other reclaimed brownfields, to form a “green remediation” site restoration process. In particular, switchgrass, miscanthus and other woody plants can thrive with little or no use of herbicides, pesticides, fertilizer, or excessive irrigation. The industry is also looking at biofuels from poplars and other trees. Perennial, long-lived crops like these save energy and other resources because they practically eliminate annual planting, and they could form a managed forest that doubles as a wildlife habitat and recreation area.
The Secret to Better Woody Biofuel
The North Carolina team tackled one major hurdle facing biofuels from woody plants, and that is the difficulty in breaking down lignin, the substance that puts the “wood” in wood, in order to get at the carbohydrates needed to produce biofuel. The conventional process relies on harsh chemicals, which in addition to the undesirableness of using toxic chemicals also wastes a good deal of the carbohydrates in the form of a liquid byproduct. Some of that waste could be recaptured with additional processing, but that would involve more expense and more energy. The researchers found that they could accomplish the same thing in a single process by exposure to gaseous ozone. The new process involves no liquid or solid waste.
More and Better Biofuels
The North Carolina development is just one example of an industry that is moving forward with the help of a network of academic research institutions. Another example is the University of Florida, where researchers have been tackling the lignin problem from another angle by using a tobacco-derived enzyme to break it down. For now the research is focused on biofuel from crop waste such as tobacco stalks and orange peels (Florida alone generate enough orange peels annually to produce about 200 million gallons of ethanol), but it could also be used on newspaper, straw, and other woody biomass. The focus on local crops (local to Florida, that is) like tobacco and oranges highlights another advantage that sustainable biofuels have over fossil fuels, and that is the potential for using locally sourced feedstocks to produce fuel for local needs, reducing the energy used to transport feedstocks and fuels long distances across roadways, railways and pipelines.
Image: Switchgrass (altered) by Matt Lavin on flickr.com.