“If biomass is harvested in a sustainable way so that its long-term stocks are not depleted, and (it is) burned under ideal combustion conditions, it is effectively GHG (Greenhouse Gas) neutral.”
from “Greenhouse Gas Implications of Household Energy Technology in Kenya.” American Chemical Society/Environmental Science & Technology. (2003) Authors: Rob Bailis, Majid Ezzati, and Daniel M. Kammen.
The statement above would be music to the ears of solid biomass booster the world over were it not for one tiny, almost insignificant word: ideal.
The lead-in to the full statement goes:
“Under optimal conditions, biomass combustion results almost entirely in the emission of water vapor and carbon dioxide (CO2). Water vapor, the most prevalent GHG in the atmosphere, is quickly incorporated in the hydrologic cycle with no measurable warming effect, and CO2, the most common anthropogenic GHG, can be absorbed by new plant growth through photosynthesis.”
The trouble, of course, is that biomass (wood, charcoal, animal dung), the primary source of fuel for energy poor societies in Asia, sub-Saharan Africa, and Latin America, is not normally harvested sustainably, nor is it burned under ideal combustion conditions.
The reality is that the bulk of the solid biomass fuel consumed around the world is collected from publicly owned lands and protected areas, and is burned in traditional open-fire stoves or in earthen mound charcoal kilns, both of which are characterized by their very low combustion efficiencies.
Although slightly dated, the paper cited above was based on a study conducted in Kenya that explored GHG emissions from commonly available charcoal and wood-burning stoves. The paper has not been modified or withdrawn and there is no reason to doubt its conclusions.
And what is that conclusion, you ask?
Namely, it is that:
When the emissions from charcoal production, measured in a previous study, were included in the assessment, the disparity between the GHG emissions from charcoal and firewood increased significantly, with non-CO2 GHG emissions factors (g of C/kg of fuel burned) for charcoal production and consumption 6-13 times higher than emissions from woodstoves.
Beyond the environment and public health implications, the paper highlights inherent opportunities available from a Carbon Credit and GHG Emissions Mitigation perspective. Specifically, they are that:
While charcoal consumption carries a larger burden of GHG emissions than firewood use, it also has more potential to attract investment in GHG mitigation activities. Emissions from charcoal can be reduced at both production and consumption components of its life cycle. (…) Arguably larger GHG emission reductions and energy conversion efficiency improvements can be achieved by addressing charcoal production because roughly 70% of non-CO2 GHG emissions from charcoal production and use occur during the production process.
And in case you were wondering, Daniel M. Kammen, one of the paper’s co-author, is indeed the same Daniel M. Kammen that was recently appointed to the “clean energy czar” at the World Bank.
Please see our recent post on another Daniel M. Kammen paper titled, “Charcoal: A Fuel in Urgent Need of Solutions.” (our title)
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