Are biofuels truly carbon neutral wonder fuels?

Photo by David Herron

During a speech by President Obama on Tuesday (Oct 27, 2009) about a new program of funding for smart grid technology he talked about the need for an all-hands-on-deck mobilization such as the ones which won World War II or the Apollo space missions.  He then went on to discuss legislation which would make clean energy profitable naming "clean coal technology, safe nuclear power, sustainably grown biofuels, and energy we harness from the wind, waves, and sun" as the candidates.  Whether coal or nuclear power could ever be made 'clean' is a matter of derision in many quarters (note: there is more to consider than carbon emissions).  However a recent article in the journal Science has set off a debate about the accounting which leads many to believe biofuels are carbon neutral wonder fuels.

The pair of studies in the Oct 22 issue of Science demonstrate that the way biofuels are currently produced is nowhere near carbon neutral.  Current biofuel production involves actions like cutting down rain forest in 3rd world countries to plant palm or sugar cane plantations, then converting palm oil to biodiesel or sugar cane syrup to ethanol.  Under Kyoto Protocol accounting methods the environmental impact of clearing the land to grow these crops is not counted in the carbon footprint of the fuel.

The supposed advantage of biofuels is that the carbon in the fuel came from today rather carbon which was sequestered millions of years ago.  Fossil fuels are created from biological organisms which lived and died millions of years ago, were buried, and through geological forces became oil.  Biofuels are derived from biological organisms which live today, are harvested, and the biological material converted into oil.  In both cases the result is oil but burning fossil oil causes a net increase in carbon while burning oil from biofuels does not cause a net increase in carbon.  At least that's the theory, the reality is not so clear.

What's at issue is the indirect impact of each biofuel source.  Cutting down a rainforest releases a massive quantity of carbon which otherwise would have remained sequestered in the trees.  Further the loss of rainforest means that much less global forest to convert carbon dioxide into the oxygen we animals breath.

On Oct 23 the Global Renewable Fuels Alliance issued a press release stating several assertions supporting the argument that biofuels are clean.  Perhaps the best is: Advanced biofuels are now beginning to be made from non-recyclable municipal solid waste (i.e. garbage), forestry and wood waste, algae, and agricultural residues.  An article in Biomass magazine goes further to discuss how any release of carbon from "recently living organisms" has no overall effect on atmospheric CO2 levels and is therefore carbon neutral.

A recent study by the United Nations Energy Program comes to a different conclusion, namely that biofuels should be considered climate-friendly (or not) based on the source. Whether the biofuel was made from a crop grown specifically to create that fuel, or whether it came from crop residues, this has very different implications.  The report also talked about acreage requirements for different energy sources.  For example the land required to grow biofuels can be enormous, while much less land is required to generate an equivalent amount of energy from wind or solar.

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