Cellulose vs. Maize vs. Algae: Race to Bioenergy
“I heard recently that the Southeast will eventually be known as the Saudi Arabia of cellulose,” Tiller said of the region’s ease in growing native switchgrass and other potential supplies of biomass that could be used for cellulosic alcohol production.The US consumes 400 million gallons of gasoline a day. Current US ethanol production would only provide about two weeks worth of fuel for the US. Clearly the US needs to rapidly scale up biofuels production--but not using corn. China would clearly outbid ethanol producers for any amount of corn US growers want to grow.
In 20 years of research, UT has found that switchgrass — a biennial crop that takes two or three years to reach maximum potential with minimal fertilizer even on marginal soils — in one year can produce six to 10 tons an acre compared to hay, which produces one or two tons an acre and requires substantially more fertilizer.
New research may bring that to 12 to 15 tons an acre in the next few years, Tiller said. Research also is looking at ways to more densely pack switchgrass in bales, convert it to pellets, or even alter it genetically to start breaking down soon after harvest....
Tiller explained that the process under study uses a “steam explosion” — forcing heat and steam into the biomass and then drastically relieving the pressure — to coax the sugars out of switchgrass and other biomass, making the biomass “explode like popcorn.”
A lignin byproduct can be used to make biodiesel, other oils, carbon fibers and plastics, depending on the most efficient use and market demand.
And the cellulose and hemicellulose — aside from going to the fermentation and distillation process to make ethanol — also can be used to make biodiesel and other products, depending on economics and demands. __Source
Until cellulosic biomass can be more cheaply converted to alcohols, the US will need to look to Brazilian cane ethanol, and other cheaper feedstocks such as sweet sorghum. Eventually, algae and other monocellular organisms are likely to provide better and cheaper feedstocks for biodiesel and bio-alcohol fuels. But algae still has a number of problems that need ironing out.