Ethanol Carbon Emissions

Ethanol is the most used and subsidized type of biofuel in the world, particularly in the U.S. and Brazil. Supporters claim it is a clean alternative to fossil fuels. However, there are several ethanol issues that detractors tend to point out to counter the supposed benefits of using ethanol as fuel such as ethanol carbon emissions.

The main reason for concern over ethanol carbon emissions is the amount of energy used in its production. While ethanol-blended gasoline emits less carbon dioxide, ethanol production is more energy intensive than refining gasoline, thus generating emissions from burning fossil fuels during the distilling process. On a positive note, the USDA study claims that ethanol contains 34% more energy that it takes to grow and harvest corn and then distill it into ethanol. However, another study paints a different picture. A Cornell University and University of California-Berkeley 2005 study concluded after detailed analysis of the whole cycle of ethanol production that corn, switch grass and wood biomass require 29, 45 and 57 percent more fossil energy than the fuel produced, respectively.

Another reason why ethanol carbon emissions are a concern is that its production may drive deforestation in top production countries such as Brazil, where the Amazon forest is. Although cattle-ranching is the biggest cause of deforestation in the South American country, some worry that increasing demand may lead to pressure on forest territory.

One of the biggest hopes for ethanol technology and ethanol carbon emissions is the development of ethanol made out of non-food materials such as switchgrass, prairie grasses and woody plants, which could be converted into so-called cellulosic ethanol. This is often called second generation or cellulosic ethanol. There is considerable research in this field and Brazil recently opened a dedicated laboratory. Cellulosic ethanol is said to have a greater energy output and lower environmental impact, and it doesn�t compete with food crops. Ethanol carbon emissions will depend on the fuel used to make it, the type of fuel employed to grow the feedstock, how much carbon the fuel itself contains, and the lost carbon not sequestered in the vegetation that the ethanol crop replaced on the land used to grow it.