As you now know, I grew up in the corn belt. When ethanol first became ‘a thing’ during the energy crises of the 1970’s, we made sure to buy fuel that included ethanol to support our neighbors and cousins, and not rely so much on imported energy.
Only later would I learn that ethanol from corn was, at best, energetically questionable. Although subject to much uncertainty, many made a good case that it took more fossil energy to produce than the energy in the product itself. It’s not surprising to me, as ethanol is just a (partially oxygenated) hydrocarbon produced in a steel tank instead of deep underground.
And yet the broader question of whether ethanol is a net help or hurt in the climate equation is a complex one. Energy use, soil emissions, fertilizer use, land conversion and other factors go into some complex calculus about a “net greenhouse gas” footprint.
Now on that topic, we have a major new paper out this week in the prestigious Proceedings of the National Academy of Sciences that considers all of those factors and comes to a rather blunt conclusion: at best current corn ethanol has a greenhouse gas footprint no better than gasoline, and more likely worse.
The conclusions are driven significantly by loss of soil carbon that comes from plowing up to plant corn. By considering a complex array of related cause and effect variables, the authors showed that the “Renewable Fuel Standards” for corn ethanol caused to the conversion of massive 1.8 million hectares (~4.4 million acres) of grassland into corn crop land just from 2008 to 2016! See the below map for where that land is – largely on the hilly, drier, or irrigated edges of the historical corn belt…
Source: Lark, Tyler J., et al. “Environmental outcomes of the US Renewable Fuel Standard.” Proceedings of the National Academy of Sciences 119.9 (2022). Fig 2C.
The astute among you will recognize that these acres are in the “central flyway” for grassland birds in North America. Now we already know that cats don’t kill grassland birds, industrial farming does, so let me be blunt in connecting dots – our current federal “renewable fuels” policy both releases carbon to the atmosphere and imperils grassland birds.
Reading on in the PNAS paper, I am shocked (but not surprised) to see that the authors hold out hope to fix this inferior carbon footprint with “continued advancements like carbon capture and storage.” So let me help dispel this delusion before it does more harm by drawing your attention to related ethanol industry news.
There’s a growing slate of proposed projects in Iowa proposing to do what the PNAS authors suggest: taking CO2 from ethanol plants and pumping it back into the ground. Most notable are the “Summit” project that would take CO2 from Iowa, pipe it up to North Dakota, then pump it in the ground and the other called “Navigator” that would run the steel pipes the other way taking it over to Illinois for disposal. Both are anchored in further public tax benefits that would pay the owners $50 per metric ton for injected CO2.
Although critics seem to be rapidly lining up to point out a various risks and weaknesses of these ethanol carbon capture and sequestration projects, no one is talking about the biggest irony of all in my opinion: Iowa, as the heart of America’s former tall grass prairie, has some of the highest potential to sequester carbon in the shallow Earth of anywhere in the country. In other words, a better solution already lies directly under their own feet!
Here’s a few numbers:
- The Summit pipeline would flow 12 million metric tons CO2 per year.
- There are 30.6 million acres of crop and pasture-land in Iowa.
- The same volume could be sequestered in Iowa soil at the rate of ~0.4 tCO2/ac/yr (12/30.6)
- If we paid farmers that same $50/tCO2, that would yield an extra $20/ac of farm income
- Farmers achieving 4 tCO2/ac/yr of soil carbon accrual would receive $200/ac.
- For calibration, the average per-acre value of all crops produced on Iowa farmland is $669/ac.
In my opinion, the story of corn ethanol as a renewable fuel is already a tragedy, and it could still become still become bigger. Let’s just stop plowing up to produce fuel for our cars and return more of our farmlands to producing real food for healthy people. Perhaps one way to think of a healthy grassland is a bunch of green, vertical micro-pipelines taking carbon out of the air and pumping it down in soil. Not only can such land accumulate carbon instead of releasing it, but the birds like it, too.
Blue Nest Beef Co-Founder & CEO