There is a well-established data set for corn-ethanol production in the US, without major differences in the physical assessment of biophysical inputs and outputs among different studies. The differences found in the overall assessment of the output/input energy ratio are basically generated by different choices about how to convert the various inputs and outputs into [...]
As observed, the production of the US and Brazil combined covers almost 90 per cent of the world production of biofuels. In 2006, the US produced 18.4 billion litres (46 per cent of the world’s total) and Brazil 16 billion litres of ethanol (42 per cent of the world’s total; World Bank, 2008). Even though [...]
According to the First Law of Thermodynamics, neither matter nor energy can be created or destroyed. Therefore, it is impossible to have an output/input energy ratio greater than 1 when considering a closed set of energy transformations. To make things more difficult, according to the Second Law of Thermodynamics, any conversion of an energy input [...]