The US Institute of Electrical and Electronics Engineers' magazine Spectrum has pronounced ethanol from corn an losing technology.
William Sweet, cites extravagant subsidises, low coal prices.It warns that burning coal to fire newer larger plants will significantly reduce the carbon dioxide benefits of using ethanol.
Sweet says
per joule of heat produced, coal releases two to three times as much carbon dioxide as natural gas, and that makes coal-generated ethanol a dubious way of reconciling energy and environmental imperatives.
And it's hard to argue with that. The benefits are reduced further if the corn is shipped any distance of course...