It would obviously be better in terms of per-panel efficiencies to be further south, but solar is still effective much further north than 40N. Nearly all of Europe from Madrid northward is higher latitude than that. And since Iowa has people there, the costs and losses of getting energy from Mexico to Iowa may outweigh much of the advantages for quite some time.

Assuming solar isn't displaced by something else, one day we'll presumably see highly insolated areas exporting power over huge interconnects, but for now, fitting a panel basically anywhere is still better than not fitting it at all.

> Also, Iowa is too far north for solar to do much good in the fight against AGW.

Absolutely not, Iowa is great for solar, it often provides more income than corn (and corn has massive subsidies), and is certainly better than most of Europe. Iowa really is not very far north

https://globalsolaratlas.info/map?c=44.374588,-77.81811,3

Generating solar power in Mexico won't keep Iowans from warming their homes with natural gas and powering their F-150s with petroleum, so solar panels in Iowa are needed for the fight against AGW.

It also ignores the reason why corn biofuels exist, because we subsidize corn production for national security reasons and there's a ton of extra produced so they try and find profitable uses for it.