The topic of biofuels is something very near and dear to my heart. The processes and products obtained could create an enormous number of jobs in the United States alone. However, with any technology, it is necessary to look at the potential difficulties to overcome, and the potential problems resulting from its use, before you back yourself into a corner. Does oil ring a bell. Therefore, I thought I would devote an entire thread to this discussion. Please try to keep the discussion intelligent. Thank you.

The following is my response to anyone who has a problem coming up with a potential downside for the use of biofuels.
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Soil erosion, and soil depletion pose significant problems to overcome. Like everything else, biofuels isn't a catch all answer to our problems. In reality it could cause more problems. For instance, in Iowa "Corn (Zea mays L.) stover is a potential biofuel; however, removing this stover from the land may increase the risk of erosion and reduce soil organic matter (SOM)." However, they are trying to find healthy alternatives, like pumping the fermentation bi-product back onto the soil to promote soil stability, or using switchgrass as an alternative crop with less agricultural engineering problems to overcome.

Sources:
http://www.cvrcd.org/ResearchPapers/...ergy_paper.htm
http://soil.scijournals.org/cgi/cont...tract/68/1/139

You must also look at the required land mass necessary to replace whatever percentage of fossil fuels you deem necessary. These are very difficult calculations, and the energy cost of production processes must also be acounted for in the equation.

Nitrates would definitely be used as a fertilizer. One of our biggest environmental concerns is the presence of these compounds within the water table.

With any economic consideration we have to account for the opportunity cost. Quite simply; if we use this land for fuel, how much food do we have to give up as a nation?

Burning ethanol will release aldehydes and other known carcinogens into the environment.

One must also consider what is known as the BOD (biological oxygen demand) associated with the product. This is simply the amount of oxygen used during enzymatic reactions associated with the microbial breakdown of organic compounds.

Given the fact that water, is also a scarce resource, we must also look at its availability.

By and large the net energy recovery of crop oriented biofuels remains relatively low, with the exception of wood, which is a semi-renewable resource at best.

By far one of the most realistic prospective studies about the feasibilty of biofuels was conducted by Giampietro, Mario, Sergio Ulgiati, and David Pimentel, and published in their 1997 paper "Feasibility of large-scale biofuel production". Truthfully, all of the research in this area of energy production has been conducted on the laboratory, bench, and production scales. The feasibility study of these scientists established three main criteria to look at the outlook of biofuel on a full economic scale. They follow:

(1) It must be biophysically possible, meaning that sufficient land and water resources are available to produce the raw materials.
(2) It must produce energy using an amount of labor that is compatible with the amount potentially available to the energy sector.
(3) It must not cause significant environmental degradation.

The study found that biofuels are not a viable resource for lifting a significant load off of the current fossil fuel consumption rate.

By and large, if this were a practical way to derive the copious amounts of energy needed in the United States, we would already be using a much larger percentage than around the order of 3-4% of total energy consumption. On the other hand, the Alternative Energy Institute estimates about 15% of the earth’s energy supply results from the use of biofuels, 35% for third world countries. It is no surprise that developing countries have a higher percentage when you consider the fact that direct combustion does not require high tech refining process. The third world method of burning these fuels is anything but green. Imagine a very large bonfire.

Fact remains, we are already using biofuels. Could creative engineering decrease our reliance on foreign oil? To some degree yes. However, biofuel is in no way shape or form a catch all solution to the problems we face. One must remember that the energy industry is a profit oriented industry, and that monetary resources sunk into research and development in these areas offsets the profit margins they have already establish in the oil sector. When the supply of oil, as well as the cost of extraction and discover, effects the price of oil and eventually shifts the demand, their profit margins will shrink. When this happens to a significant degree, you will see a change in the energy industries attitude towards alternative energies. If you haven't noticed this is already happening to a small degree. Think BP, not only do they understand this, but they have done an excellent job in their public relations and marketing.