Comment by 9rx

> over half of corn acreage is used for ethanol.

That doesn't mean much without more details. Corn is used as a tool in the crop rotation to enable growing foods for humans to eat. As we learned before ethanol's time in the sun, farmers are going to grow it anyway to support their rotations. The only question is if it is better to recapture that into usable energy or to let it rot out in the field.

> ... when taking land use into account

But if not taken into account? The harsh reality is that ethanol plants are unable to pay cost-of-production-level prices for corn. It now typically costs $5+ to produce a bushel of corn, while ethanol plants generally start to lose money as the price rises above $4.50 per bushel. You're not growing corn for ethanol. You accept selling corn to ethanol buyers when you can't find a better home for it.

Corn especially is a tough one to predict. A couple of years ago yields around here were nearly 100 bushels per acre higher than normal! Even if we put in the mightiest effort to grow exactly the right amount of corn for reasonable food uses, that 100 bushel surprise means a good 1/3 of your crop has no predetermined home right there. Of course, it can go the other way too. If you end up 100 bushels per acre short of what you expected...

Between needing to grow extra to protect against unexpected low yields, combined with unexpected high yields, half to the corn crop having no home (and therefore ending up as ethanol) isn't that far outside of what cannot be reasonably controlled for.

> To recap US overproduces calories to the point that it hurts the country.

That's fair. We don't have the technology to do better, unfortunately. Maybe once LLMs free up software developers once and for all they can turn their focus towards solving this problem?