Moonshining is less than 400 KJ per kg of source, i.e. about 1.5 KWh per kg of ethanol produced from 15% ethanol/water source. Given that one can use waste heat from almost any other industrial process the real monetary cost is way less than the cost of electrical 1.5 KWh.
>I have yet to see a significant source of usable "waste" heat that's not already being used for something else. Low-grade heat isn't helpful--you generally need reasonably high temperature differentials in order to power large-scale industrial processes.
Moonshining is 78 C degree - such cheap waste heat sources are plentiful exactly because it is hard to use for almost anything else.
>you lose energy in the cooling-and-reheating cycles.
not an issue for a 78 C process - basically like your water boiler, takes minimum of thermal isolation.
I have yet to see a significant source of usable "waste" heat that's not already being used for something else. Low-grade heat isn't helpful--you generally need reasonably high temperature differentials in order to power large-scale industrial processes.
[Disclosure: I've invested in Prometheus Fuels, but don't speak for them.]