THE COST CHALLENGE FOR BIOFUELS

Generating Ethanol from Lignocellulose Possible, But Large Cost Reductions Still Needed

"The production of ethanol from lignocellulose-rich materials such as wood residues, waste paper, used cardboard and straw cannot yet be achieved at the same efficiency and cost as from corn starch. A cost comparison has concluded that using lignocellulose materials is unlikely to be competitive with starch until 2020 at the earliest. The study…[identified] many opportunities for reducing costs and improving income within the lignocellulose-to-ethanol process, and provides insight into the priority areas that must be addressed in coming years.

"...The last 15 years has seen a massive growth of so-called first-generation processes that use enzymes and bacteria to turn the starch and sugars in corn and sugarcane into ethanol. But corn and sugarcane are also important components of the human food web, so using them for ethanol production has the potential to affect the price and availability of these basic commodities."

click to enlarge

"On the other hand, lignocellulose materials are often hard to dispose of, but they are rich in sugars that can be fermented into ethanol following appropriate processing…[C]ellulose [is] the most abundant polymer on Earth…[and] cannot be digested by humans, so using it for fuel production does not compete directly with food…The race is on to commercialize this second generation ethanol.

"…[T]he cost of building large scale ethanol-producing facilities will likely be higher for second generation ethanol compared to first generation technologies…[because] sources of lignocellulose may require significant and costly pre-treatment…Another reason costs are higher is that…[c]orn starch can be reduced to glucose with low-cost amylase enzymes, while pre-treated lignocellulose requires a [costly] cocktail of cellulase enzymes…"