The impact of fossil fuels on the environment has been well documented. They are major contributors to acid rain and are responsible for the majority of global warming (the other major contributing factor being deforestation). The question is, can biofuels, which are also basically hydrocarbons, have any positive impact? The answer to this question is not easily derived and requires that various different aspects of environmental impact be considered as follows.
Spills and Surface ContaminationBiofuels are not 100% safe. If you were to spill a large quantity of biofuel into a concentrated area, it would likely kill living organisms and contaminate surround soil or water. However, the scale of the impact would be orders of magnitude smaller than with fossil fuels.
First off, biofuels are biological molecules and this means they are biodegradable. Bacteria and other organisms that live naturally in the soil and water are able to use biofuel molecules as energy sources and break them down into harmless byproducts. This means that even though concentrated biofuel spills can kill things like plants and smaller animals, they will not persist in the environment and cause damage or make an area uninhabitable for long periods of time.
Sulfur and Atmospheric ContaminationOne of the major problems to arise from burning fossil fuels, especially coal, is acid rain that comes from the high sulfur content of these fuels. Biofuels can be produced in ways that completely eliminate sulfur and thus can eliminate this component of acid rain.
On the other hand, biofuels tend to contain high levels of nitrogen, which can form compounds that also lead to acid rain and atmospheric contamination. On the whole, the net impact on acid rain production is usually negative, meaning biofuels can reduce acid rain. Importantly, biofuels can be carefully produced to ensure that contamination is as low as possible, giving them an edge over fossil fuels because it is easier to avoid contamination in the production phase than it is to remove contaminants during refining.
Greenhouse Gas (GHG) Emissions and Global WarmingThis is the area in which the most care must be taken in how biofuels are produced. If biofuels are produced in the “correct” way, they can greatly reduce GHG emissions. If produced incorrectly, they can increase emissions. Here is how.
First, plants use carbon dioxide, the major GHG of concern, to grow and produce food. So, plants are able to reduce the amount of carbon dioxide in the atmosphere and thus decrease global warming. Biofuels, when grown from plants, can thus offset their CO2 admissions because they take up the gas during growth that is produced when the fuel is burned. The idea is that if there is a one-to-one relationship, then the gas produced is the same as the gas taken in and there is no net impact on global warming. The problem is that achieving the one-to-one ratio may be impossible.
For starters, energy has to be invested into growing the crop itself. This energy comes in the form of planting seeds, tilling and preparing the ground, and importing water and nutrients. As it turns out, you cannot get something for nothing and so many crops require more energy input than they give out in the end. In other words, if you take into account the GHG emissions that occur just to grow the crop and add that to the GHG emissions from burning the crop, there is more CO2 produced than taken up and global warming worsens. As of yet, there is no good solution to this problem. Many companies are looking to invest energy in the form of sunlight so that there is no GHG emitted during the production phase. There is still a net energy INPUT, but not GHG is produced. This seems to be most feasible with algae.
The other problem to consider is land use. If land is cleared to grow a biofuel, then the plant life that existed there is eliminated. This problem is considered in more detail in the article on biofuel drawbacks, but the main point is that carbon is produced to clear that land and the benefits of the plants on the land are lost. By some estimates and depending on the type of plant life removed, the impact could be a carbon debt that can take as long as 500 years to pay back. Again, the solution to this problem may be algae.If the above technical impediments can be overcome, then the net impact of biofuels on the environment can be limited. In such a scenario, the GHG emissions and impact on global warming will be far lower with biofuels than with fossil fuels. The feasibility of achieving this advantage remains to be seen.