Scientists: Realistic US Biofuels Potential is Massive
More than 80% of total agricultural production in the United States is used to feed animals, not human beings directly;
Our analysis shows that the US can produce very large amounts of biofuels, maintain domestic food supplies, continue our contribution to international food supplies, increase soil fertility, and significantly reduce GHGs. If so, then integrating biofuel production with animal feed production may also be a pathway available to many other countries. Resolving the apparent “food versus fuel” conflict seems to be more a matter of making the right choices rather than hard resource and technical constraints. If we so choose, we can quite readily adapt our agricultural system to produce food, animal feed, and sustainable biofuels._gcc
—Dale et al
In their study, they analyzed only the 114 million ha of cropland used now to produce animal feed, corn ethanol, and exports. Cropland used for direct human consumption, forests, grassland pasture, and rangeland are not considered. Thus, they note, the analysis provides an example of what is technically feasible, not an upper limit on US biofuel production.
For the study, they considered two land-efficient animal feed technologies: ammonia fiber expansion (AFEX) pretreatment to produce highly digestible (by ruminants) cellulosic biomass and leaf protein concentrate (LPC) production.
During AFEX, concentrated ammonia is contacted with cellulosic biomass at moderate temperatures, resulting in greatly increased production of fermentable sugars by enzymatic hydrolysis. AFEX increases the digestibility of cellulosic biomass for ruminant animals while increasing protein production in the animal rumen due to the addition of ammonia-based byproducts.
Although extensive feed testing and commercial applications have not yet been introduced, AFEX-treated rice straw has been successfully included in dairy cattle diets, and tests with switchgrass and corn stover have shown increased cell wall digestibility when exposed to rumen microorganisms.
High-protein LPC products are generally produced by first pulping and then mechanically pressing fresh green plant matter. The resulting protein-rich juice is then coagulated and dried. The remaining fibrous material is depleted in protein, but is still suitable for animal feed or biofuel production.
Animal feeding operations can be adapted to these new feeds, thereby freeing land for biofuel production, according to the authors. They also considered aggressive double-cropping, thereby increasing the total biomass produced per ha. _GCC
Even the CO2 that is produced in fermentation reactions can be filtered and used in high-value operations -- such as oil well recovery, algae growth, food production, and a wide range of chemical processes.
Instead of seeing the CO2 as a net positive, third-rate scientists and analysts tend to foolishly and short-sightedly look at CO2 as a "dangerous pollutant" and a complete liability. This faulty perspective is most likely to be seen where politics unduely influences scientific funding and publishing.
Cross-posted to Al Fin