Sunday, November 12, 2006

As the corn turns

Last week, I was at an EPA symposium about nutrient pollution in the Mississippi River Basin. Although the seminars had titles like “Nitrogen Processing in Flow-Controlled Backwater Systems of the Upper Mississippi River” and “Nitrogen Removal Capacity of Entire River Networks—Interactions of Geomorphic, Hydraulic and Biological Factors”, the same subject kept cropping up:


In 2004, the production of corn-based ethanol reached 3.4 billion gallons – or 2% of all U.S. gasoline by volume – by far the highest in history. The Energy Policy Act calls for ethanol production to more than double, to 7.5 billion gallons, by the year 2012. Since energy independence is likely to be one of the only areas of agreement between the Bush Administration and the newly Democratic Congress and Senate, it would not be surprising to see an even more aggressive policy emerge in the next couple years.

Every passing mention of the inevitable expansion of corn-based ethanol production brought sighs from many of the participants.

Why? First, most of the people I spoke with agree with the conclusion that the energy derived from corn-based ethanol is, at best, only slightly greater than the energy required in production. It may be net energy loss. Second, the participants of the Symposium have for the most part been working on the difficult challenge of reducing nitrogen pollution in the Mississippi River Basin. Increasing the production of the fertilizer-intensive crop will make it even more difficult to goal of shrinking the nitrogen-fuelled “dead zone” in the Gulf of Mexico.

To meet the 2012 ethanol goal, corn production is bound to increase [the only other option is to meet the goal purely by diverting corn grain away from feed or exports – not impossible, but less likely given the financial incentive to expand production]. That will require either the conversion of existing croplands to corn or the cultivation of existing croplands to corn.

The total area of croplands is unlikely to change significantly – it hasn’t in the past century. The best croplands were identified long ago. The change over the century has been in what crops are grown on those lands. Right now, around 2/3s to 3/4s of US croplands are devoted to just three crops: corn, soybeans and wheat.

So the thought it is that the extra corn production will come either at the expense of some other crop or at the expense of croplands currently left uncultivated. Some at the meeting suggested that farmers will replace soybeans with corn. Others, myself included, dismiss that notion: soybeans have been expanding for fifty years in the US and are too valuable crop to abandon (for ecological and economic reasons). It is more likely that either land devoted to other crops or lands contained within US Conservation Reserve Program – essentially farms are paid to leave some croplands fallow – will be used to expand corn production. Unless there is a major change in the production practices, the addition of more corn cultivation does not bode well for the nitrogen cycle.

The one reasonable argument for expanding corn-based ethanol production is that creating a market for biofuels will spur research on more efficient fuels. Thanks to market forces, corn-based ethanol may pave the way for a sensible form of biofuel production: either the “cellulosic” ethanol from high yielding grasses like switchgrass (that require no fertilizer) or biodiesel from oil-crops like soybeans, rapeseed or canola. If so, let’s hope the transition does not take too long.

1 comment:

Anonymous said...

Thanks for posting this Simon, I've been wondering about the impact of ethanol on the environment. It's deja vu all over again when it comes to finding other energy sources. The other concern I have is the pollution that goes along with ethanol plants.