This is an idea that needs to go away. We should not burn food for fuel, and there are a lot of externalities in growing corn and then turning it into ethanol that people are not considering.
Corn-based ethanol is just a very inefficient form of solar energy. Use solar panels instead and skip the middleman.
It's not that stupid, we still have many millions of people in utter food insecurity, and not just in the "third world" but also across our Western nation.
IMHO, people should come before cars when it comes to distribution of food, and we should electrify automotive to get rid of the entire issue anyway. What few renewable fuels we have, we will sooner or later need to power air flight and ocean-crossing ships, as we do not have any alternative to some sort of combustible fuel for either purpose.
As an aside, corn ethanol is not made with the type of corn that could be used for human consumption. We could use those same fields to produce human food, but refer back to the first paragraph of this post for why we don't do that.
A diesel ICE engine can be surprisingly efficient and is not particularly expensive compared to a turbine.
You can also run a diesel engine on green fuels.
Reliability, efficiency/cost of operation, and noise is probably the priorities that come way ahead of weight.
Compared to reciprocating engine-powered CHP, they tend to produce a slightly higher proportion of their energy output in the form of heat than electricity, and the plant is about about 60% of the volume and half the weight - so they make most sense in constrained spaces or for rooftop installations.
They'd certainly be quieter than a microturbine and not need fuel brought in.