There's lot of factors at play here:
- Location for generating PV
- Redistribution of food (both for livestock and human) production
- Environmental impacts of PV vs livestock vs depletion of native prairies
Point still stands...if you replaced all of the land used to produce ethanol with PV, you would create a surplus of energy that is higher than anything we could imaginably consume today (hint - China is essentially already doing this)
Ethanol from sugarcane makes a lot more sense. Corn ethanol is just a wasteful subsidy for farmers paid for by drivers.
What is the problem, that sounds great? 30% free output out of your input is staggering honestly. Thank you sunshine and atmospheric CO2. You don't have to use fossil fuel for this. You can potentially run the farm equipment off ethanol if it were designed as such.
You can also only grow sugarcane well up to usda zone 8. Some people can do it as an annual but I guess it is tricky. Corn you can grow all the way into Canada.