Many countries are running on part-ethanol already; the UK is on "E10" (up to 10%)

partial ethanol and full alcohol are not even close.

Close enough. E10 is enough to see most of the issues you will see with pure Ethanol. Most engines just need to run is different fuel maps. ideally you would make other changes (increase the compression ratio), but they are expensive.

Some engines (SAAB, I'm looking at you) will detect knocks and adapt the map on the fly.

Then, there's the more insane stuff:

https://www.motorauthority.com/news/1024086_ethanol-powered-...

* * *

Which was why I didn't say "all" or anything like that. But basically a lot of engines from Ford and Volvo can run on ethanol. Any old iron block can if you replace pipes and hoses. And so on.

Sure, if you rebuild an engine to run on ethanol it'll run on ethanol.

Which is why I said converted. The wrong kind of rubber will get brittle from ethanol. But for an iron block, it's not rocket science. Any shade tree mechanic could do it.