corn stover

Cellulosic ethanol has finally arrived

It’s been the Holy Grail of biofuels for decades, a will-o-the-wisp, always promising great things over the horizon. But it finally seems to have arrived. Cellulosic ethanol, capable of recycling crop wastes into fuel, may be here.

On the day before Halloween, the DuPont Chemical Company opened what it claimed to be the world’s largest cellulosic ethanol plant in Nevada, Iowa. The facility will use cornstalks, leaves and corn cobs – called corn stover, the organic material usually left in the fields – to manufacture ethanol that can be used as a substitute for gasoline in our cars.

The new technology may take a while to take hold, but it promises to upend the ethanol industry and pose an even more formidable challenge to the oil industry. Ethanol will be much more available using the new technology. It will require less land or the conversion of marginal land to crops. It will put an end to the debate over whether corn ethanol is really reducing oil imports and making improvements in the environment or not. And it promises to create a new industry in the Midwest farm belt – even though it could halt the current practice of sending 40 percent of the corn crop to the ethanol refineries. It is bound to be a “disruptive technology.”

Cellulosic ethanol revolves around the cellulose molecule, the tough, long-chained molecules that plants use to build their structural material – stems, leaves other protective fibers. The seeds in an ear of corn are made of much shorter molecules and break down easily to the compounds that make up ethanol. But the cellulose molecules survive all kinds of fermentation processes and retain their integrity. They can be broken down by extreme heat, but this uses much more energy than it produces and is therefore a useless effort.

The only way to break down the cellulose molecule economically is by utilizing the bacteria and their enzymes that split the long chains in nature. Cows have bacteria in their stomachs that break down cellulose, which is why they are able to eat grass. Termites and other select organisms can do the same thing. But cultivating these bacteria on a commercial scale has proved impossible.

That is, until now. Last year Poet, another Midwestern ethanol refiner, opened a $275 million facility in Emmetsburg, Iowa, in a joint venture with Royal DSM, a Netherlands biotech company. The King of the Netherlands attended the opening ceremony. Abengoa, a Spanish energy company, also completed a $500 million facility in Hugoton, Kansas, that will produce 25 million gallons of cellulosic ethanol annually. But the DuPont operation in Nevada surpasses both these efforts. It will produce 30 million gallons a year and will be ripe for expansion.

DuPont has already contracted with 500 local farmers to provide 375,000 dry tons of corn stover, meaning it will draw all its feedstock from within a 30-mile radius. The plant will provide 85 full-time jobs and more than 150 positions of seasonal employment in the local area. Iowa Gov. Terry Branstad, who attended the opening, said, “Today we celebrate the next chapter in the rich history of agricultural innovation in Iowa. Using agricultural residue as a feedstock, we will be creating a fuel that brings both tremendous environmental benefits to society and economic benefits to our state.”

The use of corn stover as a feedstock instead of the grain of corn promises tremendous advantages both in energy gain and in carbon reduction. A study by the Environmental Working Group, a Washington-based non-profit, and two University of California professors, has determined that ethanol from corn stover has a life-cycle carbon intensity 96 percent lower than gasoline. The study, titled “Better Biofuels Ahead,” said that switchgrass, a popular alternative for cellulosic ethanol, only reduces carbon intensity by 47 percent. However, the really controversial matter is their quotation of an EPA study stating that ethanol from corn seeds actually increases carbon intensity by 30 percent. This is another piece of the puzzle whereby environmentalists have been backing away from corn ethanol as an environmentally sound substitute for gasoline.

Of course there are dangers in over-utilization of corn stover for ethanol. Farmers usually leave the stalks and other elements on their fields as ground cover for the next crop. As the Environmental Working Group report says:

Corn stover acts as a barrier to rain and wind; removing too much stover exposes soil to the elements, increasing erosion. For this reasons several studies caution not to remove more than a third of the stover from the soil.

DuPont has already said it will abide by these rules and not take too much stover from farmers’ fields.

EWG recommends phasing out the corn-ethanol mandate and devoting the government’s efforts to developing the cellulosic industry. This is unlikely to happen anytime soon. It will be a long while before the cellulosic industry can produce anywhere near the 14 billion gallons of corn ethanol currently being produced. And it will probably be a longer time before selling stover off their land can match the profits that farmers reap from selling their corn crop for ethanol.

But the opening of the DuPont plant in Iowa is the dawn of a new day – an era in which cellulosic ethanol may provide a much healthier substitute for gasoline.

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