Let’s Not Forget Carbon Just Yet
by Ron Alverson, President, American Coalition for Ethanol
Reports of my death have been greatly exaggerated…..that famous quote attributed to Mark Twain seems to be a good fit these days as it relates to the national interest in reducing carbon emissions. Without question we are seeing a de-emphasis on lowering carbon at the federal level but it does not mean the issue is going away or that low carbon fuels have no value. While the pendulum appears to be swinging from one extreme to the other, it is likely to settle somewhere in the middle and fuels that can help automakers achieve efficiency standards, which are arrived at by determining their carbon emissions, are going to be important.
California and the “left coast”, as well as numerous other states have or will be adopting low carbon fuel standards. Countries importing our ethanol are requiring a low carbon pedigree and the potential for a carbon tax all remain drivers to reduce our footprint.
And this is good news for ethanol, despite the myths, misinformation, and prejudices that have dogged corn ethanol for years But why does corn ethanol get such a bad rap? What is it that makes EPA and many environmentalists cover their eyes and ears when we provide solid, scientific data that turns those myths and misinformation upside down?
For starters, the debits applied to corn ethanol for the use of fertilizer are based on numbers we have left behind years ago. Similarly, dramatically higher corn yields and reductions in tillage over that past 30 years have reduced soil erosion and built soil carbon stocks in corn fields. These two revolutionary changes have made old carbon intensity calculations obsolete.
Recently, Dr. Paul Fixen, the immediate past president of the American Society of Agronomy penned a piece called “Progress in Agronomy: A Story Worth Telling”. http://www.croplife.com/crop-inputs/progress-in-agronomy-a-story-worth-telling/ Dr. Fixen described the changes he has witnessed in Mid-West corn production since the early 1980s. Here are the facts: Per acre corn yields have increased by 70%; yet, corn nitrogen fertilizer per acre use has only increased by 5%; percent of cropland under conservation tillage increased from 18% in 1982 to 42% in 2008; soil erosion has been reduced by more than 40% since 1982; and more than a quarter million soil tests from multiple soil testing labs have confirmed that the long decline of soil organic carbon (SOC) has been reversed in the Western corn belt due to higher yields and reduced tillage. On average over the past 20-25 years, these soil testing lab data indicate that SOC has increased 25%!
So, what does all this good news about corn crop productivity, fertilizer use efficiency, and soil health improvements have to do with the carbon intensity of corn ethanol fuel? Big reductions! But only if the currently used models are updated to reflect these facts. As of today, life cycle GHG emission models used to determine corn ethanol fuel’s carbon intensity do not consider or account for a biofuel feedstock’s effect on SOC stocks. Small annual increases in SOC stocks mean big reductions in corn carbon intensity. These increases, when accounted for in GHG models, reduce corn ethanol fuel’s CI by 40% relative to the GREET 2016 model’s latest assessment!
Currently, GHG emission models calculate that the manufacture and use of nitrogen fertilizer to grow corn produces more than 40% of all GHG emissions during corn production. Unfortunately, fertilizer use emission factors used in models rely on decades old data. In the 1980s and 1990s, corn growers routinely applied about 1.25 lbs of nitrogen fertilizer to produce a bushel of corn. Over the past 5 years, growers have used .9 lbs of nitrogen for each bushel. This means big improvements…… far less surplus nitrogen is left in soil and far less losses of N emissions from soil to our air and environment. In their 2015 report to congress, the Gulf of Mexico task force published stream water quality data that indicted that total nitrogen fertilizer in Mississippi River water has been reduced by 30% over the past 35 years. We are working with the Urban Air Initiative and others to get EPA to update their models with these facts which would show nitrogen fertilizer related emissions would be reduced by 40%.
Big improvements in nitrogen fertilizer use efficiency and soil carbon stocks mean big reductions in corn ethanol carbon intensity. The wait is over, the low carbon, high octane, economical, plentiful and home grown renewable fuel is here today!