Use of corn for ethanol has been argued for now decades.  It was topical in my graduate time at K-State as a poor conversion of energy.  Not a lot has changed in the essential science.  The use of a premium via lowering the CIS helps with this conversion issue.  The other reality is that a third of all corn goes to distillation these days. It absorbs supply and stabilizes demand.  The US dominates world ethanol exports.

Another set of rules of thumb to gather around the 45Z CIS are the embodiment into foods.  40+% of ethanol carbon footprint is in the corn feedstock likewise for other commodities like meat, milk, and eggs.

If the trumpco Sec of Ag and Treasury can get off their butts, all the fundamental features are in place.  Was is even more interesting than the kick-starting via ethanol, are the other corn and bean CIS embodiments like eggs, sausage, milk, McDonald burgers all looking for ways to lower their carbon footprints.

The other neat feature is that the market place and preference by offering premiums for low CIS commodites, is that as the CIS approaches 0.0 both soil health and carbon sequestration has increased propensity to become a capital asset of the farm.