thanks to Greener Magazine
Since I published The Ethanol Conundrum last week, I have heard from quite a few people who expressed interest in biofuels. I thought it appropriate, then, to share the EPA’s (Environmental Protection Agency) recently released recommendations and findings for biofuel production and usage.
In previous EPA reports, the lifecycle global emissions were never taken into account, but that has finally changed. Lifecycle emissions are indirect carbon dioxide emissions caused from clearing land, removing plants (that trap CO2) and releasing carbon from the soil. This caused biofuels to look much greener than they really are. The source of these emissions was not always clear, or easy to measure, and so government agencies often left them out. This omission is why there seems to be a completely different number for biofuel global warming impact when looking at different sources. Some reports find ethanol from corn to be a net loss in energy while others find a great reduction in green house gas production. While there are still some discrepancies between researchers with different goals and funding, this new model from the EPA does a solid job in explaining how renewable fuels will effect global emissions.
First, to explain what lifecycle emissions are, it is important to understand the consequences that farming has on CO2 emissions.
thanks to the Clean Air Task Force
This map shows that by growing fuel in developed countries, the added costs, and reduced food production, necessitate the clearing of previously unused land, which releases large amounts of global warming gasses into the atmosphere. It takes many years to begin to overcome this surplus of emissions, even with moderately efficient feedstock, like sugarcane. In order to take this into account, the EPA has done a little fancy math and calculated the reduction in emissions over the first 100 years. During this time, Ethanol from corn only reduces the total green house gas (GHG) emissions by 20% and it takes 33 years just to break even. Conveniently, the percent reduction needed to be considered a renewable fuel is also 20% over 100 years. In the following graph from the EPA, you can see the various reductions for different types of feedstock. From this, it is clear that the only source truly useful is switchgrass because of its short pay back period (3 years).
thanks to the EPA
Switchgrass is a robust grass that is native to the US, Canada and Mexico, produces high yields and can grow on fairly pour farmland with little input needed. The problem with it is that cellulosic ethanol (using stalks instead of grains and sugars) requires a different sort of processing, and while a significant amount of work has been put towards this goal, a full scale industry is not in operation. On the other hand, since the entire plant can be used, much less land is needed to produce the same amount of ethanol. From this analysis, I don’t see the point in trying to produce ethanol from corn or soybeans. Even with sugarcane, I have significant doubts. In all reality, we need to make cellulosic ethanol a viable option and we need to stop wasting time with other choices that obviously are not going to of much use. I know that biofuel is an easy short-term solution, but I have been disappointed with our government’s insistence on it. It is time to start thinking a little farther into the future and work on solutions that can actually fix the problem. If that solution is going to be biofuel, then cellulosic is the only way to go.
For a more detailed explanation of lifecycle emissions and how they relate to global warming, this is a great book that goes into the science of climate change.
