Thursday, September 27, 2012

Biofuels might not be so green after all

As we saw yesterday, it's very easy to be excited about certain aspects of bio-based materials (They're GREEN! They're sustainable! And biodegradable! And...) while overlooking other aspects (waste water, waste biomass, waste gas emissions...). While yesterday I discussed polyydroxybutyrate (PHB), today's topic is biofuels.

A new study from EMPA (the Eidgenössische Materialprüfungs- und Forschungsanstalt, which in English is the Swiss/Federal Laboratories for Materials Science and Technology) shows that when a complete life cycle analysis is undertaken, most biofuels are actually worse for the environment, human health and resource use than petroleum fuels. To put is simple, these green fuels are not green at all.

You can read the entire 113 page report or look at a summary such as this graph:(click on the graph if it is too hard to read the fine print)
The only two aspects where universally biofuels meet or beat petroleum are in a reduced global warming potential and ozone depletion. Looking at the other extreme, land and water eutrophication is the biggest downfalls across the widest range of biofuel alternatives.
"Biofuels can allow the reduction of fossil fuel use and of greenhouse gas emissions but with the risk of shifting impacts and creating new environmental problems; indeed, only very few biofuel pathways show lower or at least no higher impacts than the fossil fuels for all indicators. The most promising pathways are those based on methanisation of residues or on reforestation activities."
While some may see this a justification to keep going with petroleum ("Drill Baby Drill!"), this report shows the strengths and weaknesses of the various options, but also cautions
"The study confirms the high diversity in the impact patterns of biofuel pathways and therefore the necessity of assessing biofuel projects with specific data. The uncertainty of the results is high due to lack of data and modelling uncertainties. There is for example a need for more specific modelling of agricultural N2O. This uncertainty should lead to general caution when promoting biofuels."
Like most of the large questions facing civilization, we don't know the answer ahead of time. We just have to keep an open mind to options as we go along. Running open-ended experiments is a discomforting thought to scientists and engineers, but we really have no choice, do we?

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