One study by Battelle Laboratories of Columbus, Ohio, commissioned by the American Petroleum Institute , concluded that it takes something on the order of 2.2 times the energy gained from alcohol to produce it. That pretty well jibes with figures from many earlier studies by the U.S. Agriculture Department, the University of Illinois, the University of South Dakota at Brookings, Louisiana State University, and Mobil Oil's Research and Development Corporation, to name but a few. But these studies invariably compute every BTU of production costs and assign little if any energy value to all those corn by-products, all of which in the normal run of agricultural production could have been derived from the same crop with the same energy expenditure without producing a single drop of combustible fuel in the process. It is true, we did not assign any energy value to the corn byproducts. But, according to Scott Sklar of the National Center for Appropriate Technology and an avid alcohol fuels proponent, it's spurious to calculate alcohol's energy trade-off strictly in relation to fossil fuels such as coal, natural gas, or oil, which were most frequently used in tests as the distillation fuel.
Electricity has the same problem.
It takes four units of coal to get out one unit of electricity. But the reason we do this is because electricity is a very viable energy source. You can distribute it easily. The same thing is true of liquid fuels. It's very difficult to use coal in your car, or wood in your car, or cheese whey in your car.