Des Moines Register
03-18-07
Q&A on the future of ethanol
PHILIP BRASHER
REGISTER WASHINGTON BUREAU
Q. How long can Iowa stay No. 1 in ethanol production?
A. Hard to say. Iowa is the top producer of corn, so it makes sense to build
ethanol plants here. But in the future, ethanol will have to be made from other
plant material, such as grasses and trees, in addition to corn. Economists say
much of Iowa's land is so fertile and expensive that it doesn't make sense for
farmers to change from relatively high-value crops like corn to switchgrass. Land
in Southern states would be better for growing switchgrass for fuel on a large
scale.
Q. How much ethanol will Iowa produce?
A. The state's existing projects can produce 1.7 billion gallons annually, and
plants that can produce another 1.6 billion gallons are under construction.
Eventually, the state could produce 2 billion gallons or more a year from cornfield
residue and perennial grasses, says Paul Gallagher, an Iowa State University
economist.
Q. The federal Energy Department's goal is to produce 60 billion gallons of
ethanol nationally by 2030. Is that realistic?
A. Not with corn. That goal assumes that most of the ethanol will come from
sources of cellulose - cornstalks, wheat straw, grasses, fast-growing trees, even
garbage. While the National Corn Growers Association estimates that 15 billion
gallons of ethanol could be made from corn by 2015, projections by the Energy
Department don't think that's possible even by 2030.
Q. Is it feasible to harvest enough cellulose to make 60 billion gallons of ethanol
every year?
A. The Energy Department thinks so, but critics say the department is relying on
overly optimistic estimates. By far, the biggest source of crop residue is corn
stover, the stalks, cobs and husks that are left after the grain is harvested. The
department estimates that the amount of available stover could rise from 225
million tons to 375 million tons through new seed varieties and that nearly 70
percent of that could be harvested for ethanol production. However, removing
stover from fields is controversial because of the material's importance to soil
fertility and erosion control.
Q. That's a massive amount of material. How will it be transported and stored?
A. Experts say that may be the biggest challenge of all. A typical ethanol plant
would need the equivalent of 80 truckloads of stover every day of the year. (If the
material isn't tightly packed, many more truckloads than that would be needed.)
Delivering that much material to an ethanol facility within a short time after
harvest, so that it can be stored properly to prevent decay, would be very difficult.
Q. What does it take to make ethanol from cellulose?
A. Cellulose is made of fermentable sugars just as corn is, but the cellulosic
sugars are harder to get to. The cellulose must be pretreated with heat and acid
to break it down. Then, special enzymes, such as those used to give blue jeans
the faded look, and microorganisms are used to produce the sugars and then
ferment them into alcohol.