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Biofuels reconsidered

CPL Press, Biochemical routes to liquid biofuelsBiofuels – fuel derived from organic matter – are generally considered to be more environmentally friendly than fossil fuels in that they are renewable and, in theory at least, “carbon neutral.” However there are downsides to biofuel, such as the energy and resources to produce them, and in the case of fuel produced from food and oil crops, potential impacts on food markets. The picture is more complex.

Are some biofuels more environmentally friendly and beneficial to the socio-economy than others? What is the place of biofuels in the overall energy equation of the future? Without going into a long discussion, here are a few proposed maxims that may be useful in considering such questions. These are derived from some discussions a few years back and intended as relative measures rather than absolute binary choices:

  1. Gathered is better than purpose grown. For example deadwood chopped into firewood is less costly to produce (land, water, inputs, energy) than crops grown for biofuel. Waste matter is a potential energy source that could be “gathered” for that purpose, although requiring processing. Jatropha seeds collected from hedgerows costs little in land compared to a plantation of jatropha created for seed production. Production of algae for conversion to biofuels requires infrastructure and much water. One problem with gathering biomass suitable for energy from nature or human activity is that it tends to be diffuse and limited (with the possible exception of human waste products). For example wood waste as a byproduct from logging and sawmills is a source of energy but the volume produced (which can be collected) is a function of other activities and not one easily increased.
  2. Less processing is generally better. Processing does have the advantage of yielding a more concentrated and often more portable energy source, but it has energy costs and externalities. A simple example is turning firewood into charcoal, which involves burning off the volatile constituents (energy generally wasted) but yielding a lighter and more concentrated energy source. Towards the other extreme, fuel ethanol production from corn (maize) is a multi-step process. The energy balance (output from a given input) of such processes is a matter of some controversy, but probably all would agree that if it were possible to produce a given unit of biofuel with less steps and inputs, the outcome would be more positive.
  3. Less distance is generally better. Getting firewood locally (as we do in our home for a fireplace insert) involves less cost, and in theory at least, more potential for responsible management, than shipping firewood around the world. Of course no one proposes import-export of firewood, but other diverse biomass is exported for production of biofuels. One example is palm oil from Southeast Asia to make biodiesel in Europe. A big part of this is transportation, which of course is part of the fossil fuel market too, but with less flexibility in the case of biofuels (one can find petroleum sources in various locations, but some types of biomass inputs like palm oil are very region-specific and possibly not substitutable).
  4. Small is beautiful. Smaller scale production of biofuels has less of an impact on the environment and economy than larger scale operations. A big issue is use of finite land and water resources. Some years back I worked on a project in Mali which had as a major goal promotion of planting woodlots with villages which could then, so the thinking went, harvest wood from those lots for their their cooking needs. Small and local, this might seem to make sense, but in fact it meant taking land out of agricultural rotation for an uncertain future outcome. An even smaller and apparently more successful approach in another region of the same country a few years later was planting of jatropha in lines along roads and field boundaries – no lot required. Contrast with large plantations of annual biofuel crops which can have enormous impact in an area to serve needs far away (impacts being potentially both positive and negative, but with clear opportunity costs for types of land use and agriculture).

Another perspective on biofuels is worth adding to the mix here. Generally biofuels are considered along with technologies such as solar, wind, and wave energy as cleaner alternatives to fossil fuels. However biofuels work on the same paradigm as fossil fuels – burning something to release energy (with byproducts such as carbon dioxide). It can be argued therefore that biofuels are actually more like fossil fuels except for the premise that they are carbon neutral, and the fact that diverse biomass sources for biofuel production are arguably less substitutable than say crude petroleum from diverse locations.

Again the picture is complex, and all this is not to say that biofuels as a whole are bad. Rather there may be some types of biofuel and approaches to incorporating them into the larger energy equation that make more sense than others. Conversion of waste into fuel would be elegant – turning a problem into a resource. On the other hand, devoting land and water to growing crops or other biomass specifically to process and ultimately burn doesn’t seem sustainable in a world faced with a growing population and impending climate changes.

Longer term, the energy market will certainly follow Buckminster Fuller‘s observation about the “ephemeralization” of technology, which we see the beginnings of already with advances in utilizing solar and wind power. Eventually the burning of substances for energy will become marginal in the global energy equation.

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